Plan seems to be subject to free-rider problem of any communist pooling. Low performers get better $:effort ratio by lowering effort, and team ROI slips until everyone wonders why they started it.

Why not use the pooling to skew reward in favor of performance? pay 10% ROI for each game (for that steady income), and pay winners their actual winnings on top. Haven't done the math, so likely not sustainable, but there should be a pattern where 1st place winners make more than they would otherwise, and all other performance paid a nominal amount per game. Incentive is to win, which drives up ROI and keeps good players in it without the sense they're supporting freeloaders (though the investors then favor 2nd and 3rds.... so my idea is flawed too...).