Alan Schmidt on The Post-Bourgeois Proletarian

Even in a high fantasy setting, it always made more sense for the end-game to be that the once weak but scrappy level 1 fighter and sorcerer build up wealth and prestige to the extent that the fighter now has his own army and the sorcerer consolidates and controls all the most powerful magic guilds. This culminates in a final grand battle against the Lich King over a massive battleground. Basically, the start is dungeon crawling and the finale is solidifying an empire. It should feel like two separate games as the campaign progresses. The only way a total dungeon crawl campaign makes sense is if the players are trying to flee a totally hostile world, say after getting dropped there by a malicious wizard.