Team Fortress was a mod. Counterstrike was a mod. DotA was a mod. Really depends on what they can do with dedicated effort rather than just simply a passion project.
VR mods, they aren't really worth it IMO, I even resent the game devs who charge for separate VR releases that they usually don't even end up maintaining across different VR hardware. IMO the problem with VR is that people try to do too much with it and try to Wii-ficy the experience, and this is at the hardware level given how usually you can't even use your keyboard and mouse, having to resort to the VR controllers they came with for a much slower and less fluid experience.