Retail stores also take like 30% usually. People don't give a shit because it's not unusual and any option that takes less is worse in some way.

I agree with the fact that 30% is a lot, but the way you've written it suggests no one but Valve takes a 30% cut. 30% is pretty standard for game platforms. Steam, GOG, Apple's App Store, Google's Play Store, PlayStation's PSN, Microsoft's Xbox Store, and Nintendo's eShop all take 30%. The only reason why Epic Games takes less of a cut is because it's the only way they might entice games to get published on their platform.

Steam is super problematic in so many ways, I just don't think their 30% cut is as big a deal as everyone thinks it is.

It's more complicated, because Valve absolutely isn't perfect and contributes to problems, and most of that comment is valid. I still wouldn't boycott them as it stands, because I do see them as the best option and don't mind them getting some of my money.

The best alternatives have their own flaws, GOG using GenAI in official promotional material and no Linux launcher, itch barely having a launcher, which is valid, but is severely lacking compared to Steam.

it's closed source how would anyone check anyway?

That is kinda true... I don't think Valve actually says that, but I don't think there's a way to tell, so people can get away with not disclosing it.

I'm an adamant AI hater, but I think this is fine. If the game runs smoothly and without bugs, I don't care if the game was programmed with AI. If it's a buggy mess, it gets filtered out with all the other asset flip garbage. Steam supports returns and you can pretty quickly determine if a game is garbage within that return window, and leave a review saying it's a buggy mess. Sure, it's an extra step but almost all of the buggy garbage on Steam is immediately apparent from the Steam page or a AAA game, both of which would never get my purchase to begin with.