It can be. I think in the old days, or maybe more in the days of our youth as gamers, we were most attracted to zonky high-level antics and played a very reward-driven game where getting lots of lootz and being 29th level was all the rage. The guy that DMed mostly for me, and myself, had a kind of shared world back then, characters migrated back and forth between campaigns a lot. His campaign was FILLED with these god-characters, but when we got more interested in playing a more challenging and deeper game they just faded into the background, and became in effect sort of 'demi-gods' or whatnot.
I assume some similar process happened in many games, but there was a time period VERY early on when high level play barely existed. In that time period I think fighters, wizards, clerics, and thieves were all sort of on a par.
And yes, in our later play we didn't tend to play much past 9th or 12th level anymore. Now and then we'd get a few characters up to 12th or 14th level and then some sort of crazy cosmic thing would happen and the campaign would wrap up.
Now you look at 4e, and its like ITS high level play is different. Its more an extension of low-level play with epic elements added back into it in a more workable fashion. IMHO WotC made a design mistake though when they created a 30 level system. 4e should have been a 20 level system, with Epic being a sort of capstone of 3-5 levels at the top, leaving say 7 or 8 levels each of heroic and paragon tier (which is going to play out pretty much as 4e did, 7 levels vs 10 isn't a big difference). Epic then gets to be a more climactic single big story-arc or 2-3 closely related ones. It would also mean that there are 10 less levels worth of 'stuff' that have to be invented, which cuts back on clutter. Additionally bonus growth is trimmed back and you get something a bit more like 5e's 'BA' without needing to flatten the curve so much. I've found that it works well in HoML, there's a lot less 'filler powers' and such. We're nowhere near running epic level stuff, and maybe never will, but I think 3 levels of epic is plenty of room to engineer a good campaign climax. There could always be a sort of 'bonus level' that was 'level 21' for doing an apotheosis or whatever, or as a sort of post-retirement state for reprising characters in later games.