In free countries people render themselves unemployable. Ironically, if they had strong unions that would not happen, but the same conservative people who spread the transphobic hate also opposed unions and the job protections they negotiate. As to anyone in the public eye, writer, actor, politician, you are judged by what you say and believe - even if it is not what you do. Rowling generated massive good will among readers all over the world with her books that celebrated unique differences and were great metaphors on discrimination, racism and hate. The films multiplied that by a factor or 12. Then she spoke . . . . She may recover, but she tarnished her own box office, no one else, really.
The folks who are angry are angry because of what she said and that what she said has long been perceived as contrary to what she believes. It's like finding out the priest really did do what he was accused of after the church congregation vouched for him.