Yeah, payouts could be a little better for sure, but they did increase last year, with winners getting $20,000 in each division.
To be fair, the event is not set up to give the amateurs/semi-pros a good chance to make a profit. Many of the ones I know don't even exercise the buy back. If you enter and buy back in each of the three core events, your participation expense, assuming you have a roommate is about $1,500 and it's awfully difficult to cash for that amount, probably requiring a top ten finish in at least one event. Of course, the nearly elite players can make decent scores in the action room if they have the pedigree and know how to match up, and that keeps many of them coming year after year.
Of course, yours is the story of pro pool today in general. Except at the majors, only a few have much profit to show for their efforts after expenses. Not that many who go to the Derby expect to make a profit. The thrill for a lot of entrants is the chance to play against some of the true stars of pro pool. Many who don't play pool for a living would like to try their hand against a Filler, Gorst, SVB, or some other well-known pro, but only a few ever get the chance. At the Derby, win a few matches and there's a good chance you'll draw one or more of them at some point.
For most who play in the Derby City Classic, it's a vacation, not a money-making venture.