Sure, but Valve has done a lot for the Linux gaming ecosystem.
It also goes deeper than just Linux, and the Steam Deck is a perfect example of this. It's a real PC, and they allow you to use the device you bought as you wish.
Our incentives are aligned and due to how they operate it's likely that it'll stay that way for a long time.
As long as this is the case I will keep giving Valve my money and recommending their products to others.