They won't be able to just jump 2,500 DirectX and DirectSound titles off the Windows API onto Wine. Maybe if they spend a few million dollars working on bringing Wine up to date with DX11, and then they have to deal with all the development houses not switching off Visual Studio and DX12 in the coming years, because they won't want to make the jump off the M$ platform.
There's already a pretty good amount of Steam games that have native Linux versions[1], at least one developer has already announced a port of an existing game to Linux through Steam[2], and the company that handles a lot of Mac "ports" (via a Wine-like layer) has a Linux version of said layer pretty much ready to go[3].
