Because they can. Where are these small developers going to go? Itch.io, GOG, Epic, Humble? These are all options but it’s suicide to not list on the Steam store. Too many PC gamers use Steam exclusively.

Meanwhile the large developers, the ones who are making $50M+, those developers have enough pull to make the user install a custom client like Origin. That’s why Valve cuts them a better deal.

Because they can and there are is no real competition. Epic Game Store so far is laughtable attempt at pumping money into user-hostile service that missing tons of features. For now the only good reason to release on EGS is Epic giving your company money.

Disclosure: I work at small indie PC gamedev studio.

I just point out how Valve changed rules for big companies back in 2018. So they have different revenue share compared to both Apple / Google and consoles.

The fixed cost of hosting a game is relatively fixed (providing a storefront, first level customer support, license management), and the part of the cost that scales but is still cheap (bandwidth is larger for bigger titles).

However, there are many times more small indie titles than there are big successes, and it's the big titles that draw users to your platform and bring in the money.

If Valve flipped their model, those indie titles would be even more of a net drain on their profitability, while there would be more incentive for the big titles to release on their own platforms.