The reason you are being piled on is because Steam, the Steam deck, and most likely both the Frame and the Steam machine, are NOT walled gardens. It is not a console. Valve actively encourages people to use the hardware wherever and however you want, install EPIC, install Heroic, install GOG games, do whatever you want. You can buy a Steam Deck and play only and exclusively pirated games, and Valve won't stop you, they can't stop you, because it is just a computer. And it is open, and it is yours. This goes completely against all proprietary software and hardware tenets, and it is incompatible with your argument.

It is a big corporation, and it is a benevolent dictatorship. But Valve is not, and it does not try to behave like a monopoly, it is not proprietary (most of the development work on gaming in Linux is done under FOSS licenses), and it is not a walled garden.