As for the other faculties, they can still be based on government/donations or even supported by sharing profits between different faculties or labs

The gap that I was thinking about would be companies investing in researchers (and labs) and hoping they will join them after the PhD.
I believe that if Unis adopts this kind of investment as the primary source of money, it will force them to find more companies, VCs & startups to cooperate with

As someone who observes the academic world from the sidelines, I think the model needs to be rethought.
Universities should work with the public & private sectors as innovation meets financial cooperation.
At least in the applied fields of study.
The investments can be shared with other faculties 🙃