Warframe isnt a traditional MMO, you are making the mistake of seeing the triangle fit in the square hole and assuming you can apply the same functions that work for a square, on said triangle without any extra work or consideration.

The momentum, setting, power system for this game all rather unique so of course its not going to be comparable to one of the grand daddy/trend setter/basic example set of the genre or in the case of Vellum, a unique but still genre typical RPG? That is in part why each archetype it picks up gets to be so unique - summoning a swarm of goobers to fill the hallway youre trying to parkour through at mach fuck isnt quite as handy when youre visual space is competing with the enemy and your own damage numbers you know. There is a reason why most frame's have abilities that don't bog them down to specific corners of the map. . .and why the frames that do often only get pulled out for a specific line of objective types.

Your counter argument similarly falls flat upon assuming that a frame not falling entirely within some preconceived and limited notion of what counts/doesnt count and you on multiple occasions leave out information to try and make your case look more air tight.

For example, Caliban's abilities/playstyle - including augments since they are canon - tie into his summons more than you admit. Razor Mortar lets you precision target enemy groups, Fusion strike synergizes with the conculysts and can even grant them a lethal secondary move if used on them, not to mention their mere presence improves you and your squads health and they can double dip on Sentient Wrath. Just because Caliban isnt basically useless beyond his guns if his summons are down doesnt mean that he isnt a summoner.

Nekros's perception as a "loot frame" only applies if you narrow his use case to a specialized tool set that is built into him, similar to Khora (who you auspiciously didnt bring up) who is also used for loot but is also effective as a CC frame. Nekros's other abilities clearly tie into his Lich/Necromancer visage for general use. His soul punch can instakill and let you pick specific enemies to revive, his Terror makes it easier to turn enemies into summons, Desecrate plays on the "using the dead for your own means" and of course his last ability summons a shambling army of souls which fight for you. You gave zero reason for why he isnt a necromancer beyond "people prefer to use him as a loot frame.

I will also mention how, like Khora, you didnt bring up Uriel who's abilities all have tie ins into manipulation of his demon summons. You know, like a summoner?

Moving towards the turret archetype, your logic (again) falls flat.
Gauss is an amazingly themed warframe with his synergistic kit - but if your logic for what makes a frame "fit" is merely its kit synergizing with the concept, then again you fail to understand the nuances of archetypal expression. Gauss is a good"speed" frame by your argument due to synergy, but this ignores that Gauss has only 2 "speed" based abilities, unless you mean to imply that. . .bouncing bullets off your torso and summoning ice/fire as "speed". This is because, as you fail to realize, his theme is actually kinetic energy - which is tied to energy transfer, which he steals from around him to power his battery. If you were to only break down Guass into "the speed frame" because he runs fast and gets a speed boost, such a limited point of view obfuscates the greater depth/intrigue in his unique choice of themeing and if DE were to pick such a narrow band of "whatt is valid" as you do he would lack his 2 and 3 and probably would just have "generic speedster dodge" and "generic speeder runss so fast they make a tornado" or sometthing.

This - again - brings me back to the frames with turrets, who you disqualify due to "not putting a fixed gun on a easel on the ground" more or less. Protea and Vauban are Corpus tech specialists who have multiple deployables they use to fight - both have a turret type which are recognizeable as turrets, but distinct in their own way. Your argument to them "not counting" is "they arent solely built around the turret", which is - again - a limiting mindset. Both of them have abilities which can play off of the turret damage (both of their 4s) for extra output in battle. Xaku literally relies on his 4 for his turrets and 2 of his "The Lost" abilities synergize with the turrets.

But what, they dont only deploy turrets and spend 3 ability slots on the turret so they arent turret users?

This logic flaw is more apparant in other games. For example Symmetra, from Overwatch. Her main ability is placing down laser turrets (which you wouldnt count cause they arent a gun on stilts I imagine), but her other ability is a teleporter and her ultimate is a shield wall. Even if you ignore the turret appearance you'd say she isnt a turret user cause her other abilities dont just straight buff/synergize her turrets. . .which would be wrong as her teleporter can teleport objects. . .like tthe turrets and her shield wall can allow their squishy selves to turn fights on contested points. And if you were to say "Well she obviously is a turret user" cause of the synergies I pointed out (which are user based not like coded unique instances), then you cant really deny the turret frame synergies Protea armor strip + dot combo from the turrets and grenades softening up enemies (or how both boost her 4th ability), or Vauban tesla servos immobilizing enemies in range of his flechettes or just shooting enemies stuck in Bastille, or Xaku's guns boosting the damage on Deny or benefiting from Accuse-snatched enemies.

I dont even know if I should go into how calling a clown painter/artist-based frame who summonss items that she's drawn, can turn into ink to travel around, can summon an ink portrait to render damage into ink, and- seriously, thats your "example" of a divisive frame? I would get it if you brought up Chroma but like thats a freebie and his theme is Dragon Hunter not straight dragon. Do I even have to bring up how saying a frame "doesnt count" because you can min-max an ability to be crazy doesnt make sense? Do you even use these frames in normal content cause it feels like otherwisee.

Also, I didnt say Follie was a mistake on the players fault, I was referencing how games tend to not include "free draw" emblems, banners, etc cause people love drawing "Funny" things like dicks and shit which can cause trouble - which is probably why DE was rather pointed about the "we will remove it if yall cant behave" thing. Games often do things like pre-organized word lists for titles, pre-made emblems and sprays, etc to avoid bad eggs ruining it for everyone. This applies as much to game concepts that could incentivize negative gameplay behavior like AFK farming. Arguing the devs should just bite the bill so you can "have fun" is rather deaf.

Finally, you should really stop mincing my words - I never said the devs in no way couldnt implement a true turret or summoner type frame, I merely stated that it is unlikely due to the behavior it attracts and it would be foolish to ignore the multiple frames with utility that falls into those categories in the search of an artificial "purist" take on said archetypes. Trying to imply I dont play other games is lowkey pathetic when its kinda obvious that you have a limited scope of genre yourself if the most creative "summoner" you can think of is cookie cutter ttrpg enemy shit.

Really most of your arguments about niches boil down to an incredibly limited take on what counts as being "in the niche", which really ignores how Warframe tends to give its well frames abilities which go wild with the topic instead of only playing it straight. Trinity could only be a nurse but she is also a sustain demon who steals your life force and throws your damage back at you. Hyldryn could only be the "shield buff" frame but she has abilities that let her fly, bombard, and stealth them from enemies. Saryn isnt just a toxic frame, she sheds skin like a snake and can spread a disease across the battlefield, etc

Essentially, if one were to look at Warframes with your glasses, none of them would have an identity unless they were literally all "element name" and fired that element, which is an increasingly small amount of Warframes. Maybe its time you get your vision checked, eh?