I can believe that there are corporate legacy apps might look bad on 4k - you might not even be able to do a naive 1:4 upscale if it's forced to be full-screen.

I can believe that there are corporate legacy apps might look bad on 4k - you might not even be able to do a naive 1:4 upscale if it's forced to be full-screen. But I wouldn't optimize my display experience for that. However, I'm going to have to disagree strongly with your latter statement: Linux looks great in 4K. I'm running Ubuntu 19.10 to an external 4k monitor from a T430 right now (native display is a 1600x900 TN unit, which kind of sucks) and it looks great. I've had no significant aliasing or other problems. Even Windows guests with Virtualbox scaling look good. You could easily use that to run corporate legacy apps, and probably should, knowing the stability and installation difficulties associated with legacy apps.. a .vmdk is probably much easier to version and distribute!