The way to make a guild profitable for the founder/elders/certain people is to set up a large monthly fee (say, 10 gold per month, or more) for those on the bottom of the pyramid, and then have a large monthly grant for those on top. Then you need a compelling reason for people to join the guild (such as only handing out lordships and other positions to those in the guild). Having a fee to move up the pyramid helps too--possibly with very large sums to move up the rungs, with corresponding decreases in the monthly fee as they move up the rungs.
It's just like in any organization... you don't have to be the best, you just need to be first in a position to promote your peers.
