You don't need an admission of guilt to lose in court.
Currently even if they used voice clips to train a model on her voice it wouldn't be illegal. That isn't currently the case, since they say they used an other actress that sounds like her anyways.
Does Taylor Swift deserve to own a whole spectrum of voice?
No, just like she doesn't deserve to own the four chord progressions that make up her songs. If she did, she could literally sue half of all pop music.
This is why none of this is copyrightable. There are too many people that have similar voices and too many songs that use similar chord progressions.
Your fantasy where this empowers small time artists is just that, a fantasy. If we push and they come out with new laws that make these things copyrightable, you just end up with corporations owning all of it.