I can't comment on percentage payouts, makes my brain hurt...
But if WGT (as mentioned above) decreased the rake, and spread it out so even 40th place got some credits back, then (again as mentioned before) more players would complete a round...more ball hits, more revenue.
Dazza makes a great point...win a RG and the player get's less than WGT makes...he thing, only a few (compared to the many that play RG's) will ever earn enough to cash the credits in for tangible items...I think the majority of us-well me anyways- spend my credits in the ProShop for balls.
Bottom line if more feel thery have a chance, more will play...well, maybe not bottom line, but my opinion.