The amount of work needed to run high-level D&D3.X is certainly an issue, probably- it also explains why so many people seem to prefer low-level games and evangelize about their preference. What I've found, regarding the level of work needed to pull off high-level games of D&D3.X, is that less can be more if properly presented. Do as little work as possible while still retaining enough details to allow you to run the game, and aggressively take advantage of averages and "standard packages" of skills and feats (for example, no melee Fighter above level 9 or so will willingly be without Power Attack and the Cleaves, and most will have them long before that level).
You can often get by on "good enough" without optimizing every last detail, and really at truly high levels (including Epic) the most important thing from a player perspective is gear- enemy NPCs will rely on it as much as PCs do, plus you'll need to have a treasure list handy if the PCs succeed in killing the enemy (to take its stuff).
High-level D&D becomes more like a superhero comic book than a traditional sword & sorcery fantasy, and if the DM takes this to heart and runs with it then running the game at such levels becomes much easier, IMO. Adapt to the game and you can make the game adapt to you.