> If Valve pivoted into making a well-supported laptop with good hardware that ran Linux and played games...

SteamDeck is out since February 2022 and does all that. You can use a BT mouse&keyboard, plug a USB-C screen or dongle for HDMI. I did live presentations with that quite a few time. It's just a computer with another form factor.

It's not "dangerously close", it's been there for years now.

Basically only competitive gaming with kernel level anti-cheat are problematic.