Fanaelialae
Legend
IMO, HP bloat is not the reason most groups don't play high levels. I think there are two reasons primarily at work.I don't disagree, but it would also do something else; mid-high levels might actually be played, whereas they are currenlty abandoned by many groups.
One, a lot of campaigns fizzle out for various reasons before the intended end point. Leaving aside the rare game that starts at high level, that means low level games are naturally more likely vs high level games.
Two, some DMs have trouble with (or simply don't enjoy) running high level games. It's a fairly different style of DMing, IME.
Whereas you can get away pretty easily with an artfully wielded plot hammer at low levels, PCs at high levels tend to have potent abilities that can nullify all but the most heavy handed plot hammering. At low levels, if a DM wants to drag out a murder mystery plot, the witnesses can simply be uncooperative. At high levels, if the witnesses don't cooperate the party can call up the servant of a deity for the info they need.
On a similar note, the ability for a high level party to throw curve balls at the DM is vastly improved. If the low level party suddenly decides they want to go to the far side of the continent, making travel arrangements and traveling there may be several adventures in itself. Whereas the high level party can simply teleport, leaving the DM scrambling to improvise.
I enjoy running high level games myself, but even I wouldn't want to do it all the time. I've seen other DMs struggle with high level games (and I struggled myself when I was younger). That said, IME those are the two big issues that DMs face with high level games. HP bloat, if even an issue, is at best a very distant 3rd, IMO.