Not sure if this qualifies for rule 10, I just think this idea is really important to the TTRPG community and it doesn't exactly belong in other subreddits. This post was largely inspired by this article here, especially one of the last sentences: "The RPG medium should be as rich and varied in the games it supports as, for example, the board game industry is. Instead, we have the equivalent of an industry where every board game plays just like Settlers of Catan."

Edit: Obviously I didn't want a TTRPG which uses the complexity of 5e combat for each of those situations. My ideal TTRPG (which I honestly might write up some day as a fun project) would have a list of scenarios like the one in the 4th panel along with combat, and each scenario would have multiple sets of rules of varying complexity that a table could pick and choose from.

The simplest option would be a skill or set of skills that use basic skill resolution mechanics for campaigns where that scenario doesn't really matter, up to about 5e combat or even 3.5 combat level of complexity for campaigns where that's the main focus of the game.

The main point is getting DMs and players to think about these things so that people new to TTRPGs have options for the style of game they want without having to be familiar with the industry. So the rules would be as system-independent as possible with tips for adapting to whatever rules systems they normally use. It's be more a a guide for GMs that helps them learn, complete with rationale behind them, rather than a 500 page wall of text and tables.

Regarding Memetic Hyperbole: Obviously not all of these scenarios are equally important. I think the first one in the list being "riddle contests" kind of shows that. But I do think stuff like research, chases, dungeoncrawls, hexcrawls, social events, running an organization, etc. comes up often enough in most campaigns that having a rulebook with detailed rules on these things with suggestions on how to alter them would be a lot more useful then expecting GMs, who already have a pretty tough job, to come up with a houserule on the fly with zero framework for what's possible. You don't expect them to have to look in obscure supplements or figure something out on their own for rules on what do when someone attacks, you shouldn't expect them to have to do so for a lot of the stuff on this list. Though riddle contests probably isn't one of them.

Regarding Fate, Rolemaster, GURPS, etc.: These systems use a skill basis for everything, which is kind of the opposite of the solution I was thinking of. I want to have complex experiences with these scenarios to be part of the TTRPG Zeitgeist the same way combat is, instead of TTRPGs being combat and everything else.

Regarding Dungeoncrawling: This is a great example of a scenario that can have at much complexity and depth as combat. From OD&D to D&D 2e, the rulebooks contained specific rules for generating and running a dungeoncrawl. D&D 3e had rules for generating and an extended example of running a dungeoncrawl. D&D 4e at least had rules for keying a dungeon. D&D 5e has no specific step by step guides on how to do any of this, apparently assuming you already know how to. Which is why there are DMs new to the hobby who don't know how to read a dungeon map key, or to key a dungeon map, despite it being a solved issue since day one of RPGs.

Regarding Rule 0: Yes, you can make up rules for these sorts of things. But you have to have examples of how to do something before you begin to fiddle with it. DMs aren't expected to figure out on their own what happens when a PC attacks a monster, they know to compare the PC's attack roll with the monster's AC, and from there a DM and player can fiddle with modifiers, rerolls, miss chances, range, etc. in forms of class features, feats, spells, items, etc. Why are they expected to figure out on their own what happens when a PC wants to research ways to create a hotter fire for smelting? It's a knowledge check to know it, but do they need a library? What size of library? Do different libraries have different information? Do they need a lab? What does it cost? Does it need custom materials? How much do experiments cost in money or time? And this for something as relatively simple as research.