Feinstein was a Senator and CA uses a "jungle primary" for state-wide elections - there's no "safe seat" in that model.
In her last election, both final candidates were Democrats. Neither party could unseat her. Voters have been clear that they preferred Feinstein to anybody else.
So the question is why? Was it her power in the Senate? Was she particularly good at bringing pork to CA? Or was it just money and the political machine? Probably a lot of that last item - the parties themselves have incentives to keep winning politicians around - they're good for fund-raising.
The rules for rank in committees is per party and it’s only Democrats that have indefinite positions of seniority. Republicans have caps on number of terms as chair, etc.
The only people losing power with her early retirement would have been her handlers. She hasn’t made a decision on her own in a long time. And when she did pretend to do so, the handlers would “help her remember the right choice”.
In her last election, both final candidates were Democrats. Neither party could unseat her. Voters have been clear that they preferred Feinstein to anybody else.
So the question is why? Was it her power in the Senate? Was she particularly good at bringing pork to CA? Or was it just money and the political machine? Probably a lot of that last item - the parties themselves have incentives to keep winning politicians around - they're good for fund-raising.