Possibly, but that would be misguided. That's not even close to the niche ROS fills. ROS runs on Ubuntu pretty much exclusively, is essentially a mediocre messaging middleware and a mediocre build system, upon which 95% or more of the worlds decent robotics research is conducted. The main research tools, like Gazebo, require gobs of GPU processing that usually preclude virtual machines. So everyone dual boots or goes Ubuntu-native. I'm not saying that's why WSLg is being invented, but if it can produce native-ish GPU performance, that would be an amazing use case.
WSLg had an early demonstration of ROS simulations running, in fact. So I can double down on this being a use case.