We vote in primaries to avoid that.
Prior to 2012, I also believed that. Please keep in mind that the Democratic abuse of Superdelegates in 2016 to screw Bernie was so egregious that they had to reform their system to curb their egos. Some. Now they only have a 15% party leadership stake. So sanguine. So benevolent.
Many states also have closed primaries specifically to keep the party entrenched. Like where I vote, the GOP set it up generations ago, and guess which party has in recent years not lost sleep over it? Certainly not enough to bother changing it.
Primaries are the same sham as local elections with no primary in heavily single-party constituencies. Which is that the entrenched party decides who can run under their brand sure to collect people who vote down the line, and for anyone else, even lifelong registered members of that party, to run as independents. Local elections matter. So do statewide seats. And both parties want nothing more than to be in power, not to represent you.
Thinking that the other party will somehow fix what you don't like is how we have gotten here and been here since the 90s. Voting only to vote against someone else lets the slime disenfranchise you when you think it hasn't. Relying on a party to maybe, hopefully, let your vote go to who they decide, isn't democracy, and it doesn't defend or uphold democratic values. Otherwise maybe we would have something a bit more coherent than Schumer's strongly worded letters and Newsom being cautious as a lawyer "letting" one comms person tweet sass a few times for the media traction.
Maybe I didn't make myself clear:
Fuck both these parties and everyone involved. Unseat them all. Fuck both the parties, they ain't done shit but for themselves.