I'll tell you exactly how it will happen. Most sample developers are going to go out of business.
Because: I will create a MIDI line, pop it into an AI music generator and tell it to create a soaring solo violin in a baroque style. Or a pop style, or an avant-garde style.
It will spit out a wav file that will be so mind-bogglingly realistic your jaw will drop. You will pop it into your DAW, rinse and repeat.
I can hardly wait, we are in amazing times.
Yes that might be the future, but there are a few issues:
As it stands, you would be violating the copyright of thousands of other fellow musicians like you.
Because as we see happening with voices, they actually use real sources, real singers, real players.
At the moment you can have Peter Gabriel or anyone else to sing your song, I don't think Peter Gabriel and the likes would be happy to hear their own voices used against their will on probably crappy music they don't approve, and without remuneration.
Why should great violinists lend their tone and years of hard work without remuneration and without mention and without approval.
We are not entitled to pillage these recordings they are using for training.
This is with the current situation and even if they come up with the coveted "MIDI to AI" tech there are still legal and rights issues to be solved.
If a legal way brings to this then yes it is a possible future for tools for composers IMHO, and the good 'ol sample libraries already seem a bit of a relic after what we heard these days.
Maybe there will be licensed AI libraries where a single performer or ensemble give permission, under initial payment or/and a royalty agreement to use their talents to train the software.
Until then it would be probably illegal and most of all
unethical.