Mh. You forget something here. Unity has also its fanbase that does some work like writing shaders and stuff. And while GS needs this badly to substitute the own weak aspects, the Unity community builts on top of a very strong state of the art engine without ten years old ballast that not only gets engine fixes, but all the enhancemens the community is asking for, like editor enhancements. Plus next gen workflow, plus ...

At Unity they have 50 professionals working at it at the moment, growing. How much work at 3DGS? 3? 4? The gap gets bigger and bigger with every day