Long rests are basically the overnight sleep period. Short rests are opportunities throughout the day to take a short break. Both are part of the natural flow of the activity. How many encounters occur in between is whatever the party and DM fit in there following the plot of the story. In my experience, that varies and the assumptions of the encounters per rest needs to be taken with a grain of salt; possibly several grains of salt.
Generally, the number of encounters per rest increases with the level of the characters. That number also changes with environmental factors. A deep dungeon crawl with a sense of urgency and I've played or run 10-14 or even more without a long rest. A wilderness trek might be 0-2 wandering encounters per day, travel by montage, hourly encounter checks, or no different than a deep dungeon dive with a different atmosphere for a major outdoors adventure. I'll also do waves of attacks or timed events in more complex encounters.
At low levels it might be 4 encounters in a day. More encounters or longer adventuring days means less or more short rest opportunities. The 1 hour minimum requirement becomes important on those longer adventuring days to limit the number of short rests possible due to time constraints. Usually short rests are about 1 per 2-3 encounters but vary. I've seen 4 and none. I've seen the "nothing is happening and consecutive short rests" cheese camping in the wilderness too for things like multiple second winds and don't really count that as typical.
What I don't necessarily do is let the players know how many rests they can expect. I might telegraph through details if I think it's important for them to know but I like to keep them on their toes without a consistent number of rests and frequently vary it. Players seem to become more invested in the story when it's actually a story than bean counting resources for a predetermined number of encounters.
Apropos of very little, there actually aren't a lot of short-rest classes. Warlock, Monk, BM Fighter. At will? Rogue (other than AT), Champion Fighter.
Ask yourself, can we live without the above? Just EKs, ATs, and the other remaining full classes?
I think the answer's 'yes.'
That kind of misses the point of the other classes with mixed long and short rest recharge abilities. Abilities like relentless rage, song of rest, font of inspiration, channel divinity, wildshape, second wind, action surge, stroke of luck, sorcerous restoration, arcane recovery, signature spells, hit dice healing, healer feat, inspiring leader feat, and various subclass features are all short rest related abilities.
I think all classes are "short rest classes" given the hit die is a class feature. ;-)
Hit die healing is obviously easy to work around, rangers don't actually have short rest abilities iirc, and the relentless rage timer is pretty minor; however, some of those other abilities are major class features or capstone abilities. There's more to consider than a couple of higher dependency classes or subclasses.
I think the "5 min short rest, max 2 per long rest" works better due to how simple it is over omissions and changes going over everything tied to short rests. That doesn't really fit my playstyle, however.