This is completely false. They've been contributing massively to the gaming scene on Linux, especially with Proton – a more fine-tuned version of Wine, that makes playing Windows games on Linux seamless and easy.
And all these improvements trickle down to the respective upstream prkjects and default version. For example Fedora 33 should use dxvk for directx games by default, all at least partially thanks to the relenteless work of Valve. :-)