I'd say one reason is that Putnamville is the only "bullring" that runs a regular Saturday night program. Their main competition, Lawrenceburg, is a speed palace and if you crash there, your car may end up in the dumpster. Hence, guys without a lot of money are more likely to run regularly at Putnamville; especially if they're not located closely to Lawrenceburg. Both have excellent facilities and promoters, so those points are moot.