Crossover isn't aimed at the gaming crowd, but productivity software. Their builds favor stability over new and shiny compatibility/feature support. I just had a license because I like supporting CodeWeavers.
They advertise gaming as a use case for CrossOver (there used to be a separate CrossOver Games product, even, which I was a customer of), and it would not surprise me if the linux build of CrossOver sells so little they wouldn't care.
They also make a Linux build of CrossOver.