I would love to see a model focusing on making virtual instruments.

There are sample-based virtual instruments, but they do miss some subtleties, and there are physics-based ones where some subtleties are preserved, but generally worse sounding because actually modelling real hardware evolved over centuries is really difficult.

Even hardware-based instruments like electric guitars/violins/cellos etc. generally sound distinct from and less interesting than their acoustic counterparts. Electric guitar players seem to use various amplifier tricks to make up for that, and that's now a big separate instrument. But I think the point stands.

I concur. So much focus on grandiose ideas when there are so many low-hanging fruit around.

https://www.neuralampmodeler.com/