I aint worried about her career right now, I'm worried about her in general. She needs to get out of this.
I do believe they began tarnishing her career after the Femme Fatale era. They were always making her look disoriented and everything.
Now after she's out of it, I don't think she's going to retire. She's not working right now for a reason. She is gaining a lot of support from the general public (shame on them for not having supported her all this time and not seeing what every other Britney fan did) now though especially after her testimony.
When she does return to her career it is going to be completely different. EVERYTHING will be on her terms and her terms alone. Once she is out of this conservatorship, she will probably take a break, get married, have another baby and that's great. Once she focuses on her career again she's going to do the things she wants. Probably even a new record label, which I'm fairly certain is what we all want. (I'm curious if her current contract will be voided as Britney, herself never agreed to it, her father and his team did). Probably won't be a tour for a long time but that's okay.
Instead of worry about her career and everything let's just worry about her and her safety and continuing to be vocal about our support and help her fight get out of this prison she's been in and hope all these ***hol*s are caught and go to jail.