Is there any actual proof of valve taking actions to limit competition or are they just popular because they have a good business model?

They don’t limit competition, but it’s a more open question whether they are engaging in a form of price fixing.

Seems to me the only fixing they’re doing is fixing the prices lower than other clients.

Rather than what you usually hear with price fixing, where prices go up. Like Amazon with Levi jeans.

Well, no, it’s the opposite. The accusation goes that Steam strong-arms people into keeping prices on Steam the lowest (or tied for lowest) available if they’re selling the same game on another storefront. For example, Ubisoft cannot sell a game on their own platform for cheaper than they will also sell it on Steam.

Again, allegedly.

Of all the accusations against Steam, I’m most amenable to that one. I think devs should be able to sell on their personal storefronts for cheaper, if they’re going to the effort of setting up a storefront at all.

Selling on GOG or Epic for less does feel some type of way too, but I can’t say I’d block devs from doing that either.

But wouldn’t that be malicious from the dev side? “Hey, don’t bother with Steam because it’s more expensive. Come buy it here instead”. Just don’t sell on Steam if that’s an issue, but we all know they want to piggyback on the exposure/trust associated with Steam.