And which platform has the most potential buyers, by a long shot? Steam. That’s why you’re usually seeing all time lows on the Steam platform, because the sheer amount of buyers outweighs the per sale loss.
If a dev wants to make X per game, they could get X with a lower price point on Epic. To still get X, they could sell the game for a lower price on Epic. That lower price may get some people to buy the game who wouldn’t buy it for anything more.
The game can still be sold on both Steam and Epic, which is the whole point of this discussion, so Steam having a larger userbase is irrelevant.
Maybe for AAA devs. I’m thinking of indie devs as well, who may not be thinking of “big business extract max profit no matter what” optimizations.
You also seem to be leaving out of the equation that some customers will buy a game for $15 but not for $20. If selling at $15 on Steam would give too little money, but selling for $15 on Epic would give enough money, it doesn’t seem absurd selling at $20 on Steam (with the biggest market) and for $15 on Epic (with the higher margin) to reach a few extra customers with the lower price point.
The reason games go on sale so often is because lower prices can mean more sales. Lower middleman cuts can allow for lower prices.
If the userbase is irrelevant then X per game is also irrelevant. X per game matters only in the context of how many sales you’ll make. There’s a strong correlation between sales and userbase because more users means more potential sales.
Steam’s userbase is irrelevant in the example I’m explaining because they can still sell it on Steam. They won’t lose Steam customers by having a lower price on Epic.