I listed just one possible use, but I also see voice cloning and advanced TTS expanding access for evocative instruction, as an aid to study style and expand range.
Don't be afraid on their behalf. The dooming you're talking about applied to every one of the technological changes I already listed, and we employ more performers and artists today than ever in history.
When animation went digital, we graduated more storyboard artists and digital animators. When music notation software and sampling could replace musicians and orchestras, we graduated more musicians and composers trained on those tools. Now it's the performing arts, and no one in industry is going to shrink their pool of available talent (or risk ire) by daring conflate authenticity and performance with virtual impersonation. Performance capture and vfx also didn't kill or consolidate the movie industry - it allowed it to expand.
Art evolves, and so does its business. People who love art want to see people who do art succeed. I'm optimistic.