Actually, I have those same concerns. Nevertheless, I have to admit that Valve made a lot more games easily playable than Feral over the last years. Don't get me wrong. I own quite a few Feral ported games and love the quality they deliver. But I also saw a lot of devs talking about how much work it would be to support another platform (even if it could be done in 2 hours as some others have demonstrated (comparing same engines and technical complexity here)), and therefore not caring about Linux and MacOS.

So I am very grateful for the results we see from Valve. Ultimately, we might see fewer native Linux ports on the one hand, but on the other hand, we might see more people using Linux as gaming is becoming a lot easier now.