Yes but in 5e resource management is more crucial than it was before because most all classes and many magic items get rechargable powers
Relative to 3e & earlier eds, that is, yes.
In a way that makes resource management less crucial: You have more resources spread out over the party to fall back on if one player messes up. Similarly, full casters all have cantrips to fall back on, so can be a bit less cautious with managing their spell usage, and they're all spontaneous, so there's no 'wasted slots,' also taking some pressure off. Finally, even the most resource-poor classes have something to 'nova' with, so class balances is a bit less sensitive to the shortened adventuring day than it was in 3e & earlier (though, by the same token, encounter balance can swing that much harder).
- in the old days resource management was just hp and spells. So anything that provides easy rest (like Rope Trick and Leomund Tiny Hut) takes on greater import.
'Just?' Spells were all-important, and much harder to research. Leomonds Tiny Hut, back in the day, offered little more than protection from environmental factors, enemies could attack or move right through it (as could allies, only the caster couldn't leave it), Rope Trick, though, sure, was a quick rest, but at 3rd, it was your only 2nd level spell and you had to choose Rope Trick when you memorized spells (no Stinking Cloud or Web or Invisibility), so that was quite the resource expenditure. Resource management loomed very large back in the day. 5e calls that back, but also makes it a deal less challenging for the above reasons (more classes have resources, short-rest recharges, at-will cantrips & spontaneous casting for all full casters).
Of course the spells already existed.
What didn't exist, however, was such a heavy emphasis on resource depletion as a primary source of challenge.
With cheap wands of CLW rest was mainly a thing to keep the quadratic wizards happy, and any serious encounter were challenging *in its own right*
In 3e there was a strong tendency to the 5MWD, your highest level spells were the most useful, offensively, and lower level spells could be used on buffs, protections, and utilities that could be layered over yourself & your party without limit. 'Nova's could thus be insanely powerful. DMs would just dial up the challenge until you needed the Nova-power to have a chance, and that playstyle rut just deepened.
You could play about the same way in 5e, if you wanted. You can simply dial up challenges without limit, and you can offload a fair proportion of your resources in a single encounter. Concentration limits the buff-layering thing, and some classes have short-rest recharges that in theory let them take on a second encounter just as hard, but those aren't huge factors.
Therefore: that WotC didn't offer mechanical variants for rest restriction was much less of an issue.
3e offered CR and encounter guidelines, and at least in theory was 'balanced' around a long and unpredictable enough day that Vancian casters would be challenged relative to spontaneous caters relative to non-casters. That days that long prettymuch never happened was the same problem than as it is now in 5e, but, at least, this time, we have clearer guidance (as promised) as to the 'right' number of encounters (6-8), /if you want to use resource pressure to balance classes & encounters/.
If you don't, you do still have a large bag of DM tricks with which to impose balance.
Wow - just - wow...So then why have all the other rules? What does it matter if a caster has 2 spells or 50? Why track hp? Why have a game at all? Why not just sit around a campfire and tell stories?
That wouldn't exactly evoke the classic game, now would it. Casters gain spells as they level, and everyone gains hps - that sense of advancement is key.
Caster dominance being enhanced and challenges being trivialized by the 5MWD, are also part and parcel of the authentic D&D experience.
Its kinda like saying mobility is not the default for an automobile lol....
Sure, until you turn the key and drive it.
Of course, driverless cars are just around the corner, but the driving public is more accepting of improvements than the D&D community.
See I DON'T think its "funny" - I would call it extreme tragic short-sighted reactionism actually
I don't think those two opinions are entirely at odds...