That’s why I love OSE/OSR/Shadowdark etc old school styles. The team can’t really “Supernova” like they can in modern D&D.
I tend to agree. However, the modern playerbase likes the "press shiny button" modern game design while disliking the "why can't I press the shiny button all the time?" aspect of resource management.
This is natural. Gamers, people really, will always try to maximize the upside while minimizing the downside. They always want their PCs to be at full health, with their full complement of abilities whenever possible. This gives them maximum effectiveness but, more importantly, it is a buffer against PC death. Remember, players (unlike the DM) don't know what's coming. They don't know how many hp the boss has or where the traps are or if reinforcements are going to show up. What happens if the PC has a chance to rest, doesn't, and ends up dying as a result?
The smart play is to rest early and rest often, but this is in direct tension with the DM's job to control the pace and intensity of play to reach a desired challenge level. That creates an adversarial stance where anything the DM does to "make things interesting", players see as a removal of agency and a direct threat to their survivability (which it kinda is).
Unfortunatly, 5E isn't particularly forthcoming about this tension. They didn't give the DM many tools to deal with it and even compounded the problem with easy access to pace-controlling resources (Rope Trick, Tiny Hut, etc.). The party controls the pace of play, very much by design, UNLESS the DM contrives scenarios in which time pressures, environmental factors, or other consequences (random encounters) are at play. It is very possible to do this, but advice on how to do it is hard to find. The DMG needed to be far more explicit in this area.
The other problem is the 6-8 encounters/20 rounds expectation, which is too much for most groups, about not properly explained. Sure, the game works as intended if the model is followed, but if only 20%* of tables do this, something is off. *That number is just thrown out there, I have no data for what the actual number is.
This is without getting into the tension between short-rest classes and long-rest classes so that shorter adventuring days naturally favor long-rest classes. The designers maybe thought the thieves and fighters and warlocks would persuade their wizard and cleric brethren to keep adventuring with expended slots, but the reverse seems to be the case.
I've given up on 5E for a lot of the above reasons. My last 5E game used the poorly-named "Gritty Rest Variant" that should have been called the "Cinematic" or "Epic Rest Variant" of 8 hour short rests and 1 week long rests. I can't recommend it enough for the majority of D&D campaigns.
And, while I have no intention of running 5E (2014 or 2024) any time soon. If a good DM wanted to run it and wanted to impose a 20-rounds of combat before long rest restriction, I wouldn't be opposed.