just because they started packaging wine with their app

Even if that's all they did, that is more than anyone else is doing. What they really did was make nearly every game they sell easily playable without requiring you to use Windows. As byproduct, DXVK (part of Valve's Proton) provides greater compatibility and performance for Windows users as well (Intel ARC driver and DX9 game support for example). They have salaried employees working exclusively on making this work and their development is open source for anyone to use modify and share. Epic or any other store front could freely take advantage of this work and benefit why don't they do that instead of whining?