What you're saying is "inevitable" hasn't happened for the entire 20+ years of Steam. I'm going to guess Valve is going to continue being a private company and doing whatever the fuck they want, without investor pressure towards enshittification.

Steam's monopoly is actually what's holding PC gaming together. Other types of digital distribution services are so fucked up by exclusivity deals that any "competition" is always going to mean "megacorporation uses existing wealth to deny competition".

Epic is trying really hard to bring the exclusivity nightmare over to PC gaming as well, but so far Valve still holds.