They'd have to put up with Bowie, though, and that would be too much, for many people. Not to mention that you'd always be subservient to the guild founders. Realms, at least, hold the prospect of turnover, change, renewal, decay, being conquered, conquering others, etc. Guilds tend to get stale because there's no way to actually oust those at the top out of their positions. That's why guilds are so poor at making that kind of power structure. They require willing subservience, just like religions. So few people are willing to play along with that, except where required, such as in realms.