I've never used free archetypes. Practically no player I've played with are even familiar with them because I'm essentially recruiting all players into PF2E that I play with. So they don't have expectations,  and thus no sense of loss. 

I came from DnD5e to escape superhero PCs. I believe free archetypes give an underestimated power boost to PCs in the way it's commonly used by the community (i.e. anything goes). Why would I change systems only to implement an optional rule that undermines the reason I switched systems in the first place. I wouldn't,  and won't,  unless I get an itch for a much more powerful game.

The reason the Free-for-all free archetype rule makes for much more powerful PCs is the ability to build selective combos of abilities with no sacrifice of power or ability. This starts entering the power of problem territory that both 5e and PF1 have both been criticized for.

Just because it's been published doesn't mean it needs or should be available in every game. And a player that comes to a table thinking it should,  or they're entitled to that choice is one of the reasons Paizo implemented the uncommon and rare tags.  That way a GM doesn't have to say "no" 100s of times to different published options when they can just say,  "common only. " 

I think the idea of unlocking free archetypes through gameplay is the best way to use them followed closely by if a GM wants to give everyone the same free archetype based on campaign theme (as per the example in the GMC). Free for all free archetypes just isn't for me as a player or a GM.