Why would you think PCs aren't impacted by tariffs?
Different rates for different products. I don’t follow US domestic politics that closely but last I’ve heard computer parts, displays and smartphones are at least temporarily exempted while toys (that’s consoles too) are subject to highest tariff rates.
Also, I’m describing how Valve plans to corner consumers, not the current state. So far they’re very much on track.
What is the competition on Linux? What’s their market share?