That’s definitely not the way it works.
My partner has a switch. We both created as account on it. She buys digital games on it and everything that’s installed appears in the games list.
Anyone that picks it up can see that game list. If I’m playing then I pick a game from the list and it asks which account is playing and I can choose mine or hers. Then the game starts.
And add to that the story behind DXVK, which was the turning point around 2018 for Linux gaming. Valve hired the guy who created it, so they could develop it professionally instead of as a hobbyist. With it remaining open source and free.
Yes, they do it because it helped them achieve what they wanted. But they don’t lock it down and they work with a lot of OSS which is then upstreamed.