So wouldn't the logical endpoint just be an improv night without any rules at all? If consistent rules and character-building gets in the way of the DM telling the story he wants, why have any rules at all? Why not just write up a short story with some people occasionally assisting with minor suggestions for individual characters?
Fundamentally I believe everybody can have the fun they want. Really this is more conceptual confusion for me. Personally, I believe it's just nostalgia.
The fundamental rule that in my opinion all RPGs share is that The players interact with a setting as their character with a human referee adjudicating their actions.
You do that then you are playing tabletop roleplaying.
The key elements here are
That the players are playing as a individual character.
That the character exist in a setting that they interact with (role-play, combat, etc)
That the human referee adjudicates the result of what they do.
The rules, like OD&D, are the details of how to make that happen. But they are not the game itself so to speak. The referee describing a setting, the players describing their characters, the process of describing that they do as their character within the setting and the referee describing the results of what happens. That is the game being played. Coupled with an interesting setting, like a maze with rooms filled with monsters and treasure, it makes for a compelling hobby.
The details of how this accomplished is up to you and is purely a matter of taste not requirement. If the referee is that good at communication, and know the setting, and details of what characters could do cold, then there may be no rulebooks or even dice in sight.
But that is rare, because most of us are folks who just want to enjoy an afternoon or evening hobby with friends. So rely on other people to describe how to deal with these thing or in many cases describing the setting and what can be done there (adventures).
But people tastes vary. There is a sweet spot that D&D and Pathfinder over the years manages to hit squarely. But more than a few like use material that more detailed. Settings like Harn, Tekumel, or Glorantha. Rules to adjudicate actions in more detail like GURPS, Rolemaster, etc. Other get by with less detail and stick with OD&D, or use Microlite, Fudge, etc. Some like one system approach better even though they are the same relative complexity Runequest 3rd edition versus AD&D 2nd Edition for example.
If you want to get people preference for minimal system or no system at all. Then try running a one-shot with no rules. Outline a setting or scenario. Set some character guideline (i.e. are character Conan-like, novices, veterans, or what?), have the players describe their characters naturally. Then commence play using the dice in the way that your experience and knowledge think best suits the circumstance. Just try to be consistent.