I did really enjoy 4e, though it had things it simply did not do well (exploration for example). But I'm not forwarding it as the shining exemplar of this concept- it definitely could be improved upon in a lot of ways.
The problem is, it becomes a new paradigm that people will reject because it's not what they are used to. History proved that. So you have to ease people into it. 5e actually does this, but not in a complete way. Fighters have resources (Second Wind, Action Surge) and some subclasses expand on this (the Battlemaster being the standout as a class that has limited use "special attacks").
And the Warlock's Pact Magic has what could be, "encounter magic", all that's required is a shorter short rest. You can see hints of this sort of thing in other spellcasting classes, like Arcane Recovery. The day may come when all of this is seen as so normal that you could put all classes on an encounter paradigm or close to it so we don't need to worry about needing X encounters per game day as a balancing point.
Of course, what's needed then is an absolute limit somewhere so that people who need that sort of thing in their games to simulate that feeling of characters being worn down have it. Hit points are of course the ultimate limit, but if you can heal forever that's only so useful- this is where healing surges once worked, but there are certainly other ways this could be done as well.
But this sort of evolution has to be a slow process, since there's always going to be people who want casters to have limited, but potent resources (even if the use of those resources tends to cause ample consternation, so that some champion that there must be a way to discourage or prevent their use) and non-casters to not be resource reliant. Mostly because nostalgia is a powerful force and those people feel that D&D must be this way, because it was that way for a very long time. I'm trying to choose my words carefully here- I don't mean to insult people who prefer this style of play. I cut my teeth on the same long ago and I still occasionally play AD&D (of the dreaded "Second Edition" variety).
D&D's current problem is really that it's trying to serve multiple masters, leading to a sort of cursed design where it's not fully supporting the play the PHB describes, nor fully supporting the play many fans of the game prefer- even though WotC clearly wants all groups to buy the shiny new product to keep the lights on!
Or, to quote an old song:
"I support the left, but you know I'm leaning leaning to the right!"