In reality, time constraints are always present. The assumption that dungeons and monsters will sit passively waiting for you to come in and loot them, and won't react if you take a long break in the middle, is fairly ludicrous if you think about it.Whilst this works, the trouble is, it's not usually fun, and it gets old extremely fast with intelligent players (or at least ones who aren't drinking lol) who are thoughtful about metagame concepts and/or game design, because they very quickly understand what you're doing. It's transparent, if you keep using time-threats just to try and stop players making the obviously most intelligent decision, which the rules are basically designed to make them want to take.
The challenge is that imposing the obvious consequences--either "the monsters haul up stakes and leave," or "the monsters attack you en masse in the middle of the night"--mean taking a lot of the DM's prep work and throwing it out the window. So we come up with these more contrived scenarios. However, I'm coming to think that it's worth throwing your prep work out the window once or twice--because once you establish that those consequences can happen, the players will start pushing on instead of stopping to rest. (Besides, the players will make you throw your prep work out the window anyway. That's what players do.)
It's the George R. R. Martin principle. GRRM doesn't actually kill off major characters very often. But he does it just enough to establish that he can and will do it, so when he threatens death to his protagonists, readers take that threat seriously. 90% of the time he doesn't follow through, but you never know if this time is going to be the 10%.
All that said... I do actually agree with you that 5E leans too hard on daily resources. Some players are good at managing their daily resources and others aren't, and the penalty for the latter is too high IMO. I'd like 5E to have more abilities that refresh on a short rest, and a better distribution of them among the classes.