It's worse than that...He even pays developers to make a game exclusive to his own store (and that developers' own store if it exists), which Steam (their competitor) never did.
Let's take Unreal Engine... it's free if you make less than xxx amount. However you also have to publish on Epic Store for it to be free.
When you publish to Steam, You get the -30% from Steam (which is totally worth it) but you also have to pay Epic about 35% because you are not publishing exclusively to epic store. So now you are pocketing only 35% oh your own hard work. This is made to look like Steam is bad and treating you poorly.