I disagree with your definition of “killed Linux gaming.” It killed native Linux development perhaps. But using Linux for gaming is more viable than ever thanks to Valve. They single handedly boosted Linux gaming, if anything.

And they also offer more than the competition. For a while there games on EGS were just telling people to get support on steam forums because epic had nothing for supporting games they sold. Steam has forums, screenshot storage, achievements, remote play, friends lists, a shopping cart (🙄) and is adding new features like clips. I’m not using steam because it’s a monopoly, I’m using it because it’s a better platform.