Which is a completely crap assumption, at least from any sort of non- munchkin/murderhobo dungeoncrawl. I mean, it's what 1 long rest per 24 hours, something like that? So this game expects you to get into 8 fights over the course of every single day your characters are out there walking around.
Right. That sounds perfectly reasonable.
Now see I had looked at that myself early on when I started this edition, but the mechanics exists to help challenge the players. I took a different approach than gonig by 24 hours as you said, this is a fantasy world after all. Who says a day is 24 hours there? Regardless of the length of days I do not consider every single night a full rest, it is difficult to take full rests of 8 hours on a trek when you are on a mission, especially one that has time constraints. If there are no time constraints I generally rule it as downtime and maybe the plays will have 1 or 2 random encounters but nothing taxing and nothing that rewards them very well. So they go through the standard 6 to 8 encounters before getting a long rest and they have to manage resources wisely. If you don't like doing this arbitrarily do things like throw battle in the middle of every other long rest, this interrupts the rest and they do not get the benefits. Now they are back on the same cycle count and have to manage their resources better.