It's "funny" when people try and defend Steam's cut to me, completely ignoring the fact Steam has an uncontested monopoly position in the PC gaming market. They generally claim that Steam offers some kind of services for their 30% cut though nobody ever seems to come up with what those services are beyond "discoverability" (often phrased as "access to a large audience")
Thing is for the vast majority of games they take 30% from they don't even do that at all. Unless your game is on track to gross a quarter million on Steam in the first year, the cream of the crop of indies basically, Steam does effectively nothing to surface your game. It's not like YT where there are algorithms tuned to show your video to the maximum number of people, so videos sort of get the audience their quality can maintain
On Steam you either overperform and get visibility for life or you get nothing. There's no algorithm that tries to find the setpoint for your game, just if you sell lots you'll sell more