Only if we assume a sale not made on Steam is a sale lost. If Steam didn’t get the sale and the purchase was made somewhere with a higher return instead, the dev would make more from the sale. Odds are, if Valve didn’t have almost full market control, people would still buy games, they’d just buy them somewhere else.
As long as Steam can give at least 25.8 percent more sales than Epic (or other place that offers 12%), it’s a better deal for developers as well.
(math: (1-0.12)/(1-0.30)=1.2571=1+25.71%)
Only if we assume a sale not made on Steam is a sale lost. If Steam didn’t get the sale and the purchase was made somewhere with a higher return instead, the dev would make more from the sale. Odds are, if Valve didn’t have almost full market control, people would still buy games, they’d just buy them somewhere else.