As far as I know, that's not the case with ball companies.  The details of the contract vary from bowler to bowler, but in most cases, there's at least comped equipment and a stipend.  There may be expenses, too, but my guess is that's the exception, not the rule.

Many of the exempt bowlers have sponsors, people who put up money for expenses and share in the winnings.  Ryan Shafer has mentioned his a few times on TV.  Those guys aren't necessarily being promoted by the bowlers the way staffers promote their ball companies.  They simply invest in the bowler and their return is to share in the winnings.  The return for the ball companies is the promotion and exposure they get from the staffers.

SH

Time was that on the national tour, If you were on a ball staff you recieved a salary, TV incentives as well equipment.

Now days few recieve much of a salary anymore. TV incentives have been reduced greatly. Most I believe are limited even in how much equipment they can get in a given tournament.

I've never known ball companies to claim part of the bowlers winnings.

Bowlers who have sponsor generally have to give the sponsor all money won until the sponsors amount is met. Then they have some agreement to split any additional monies.