They’re more than willing to put pressure on the left leaning members, and work against their reelection. They just won’t do it to anyone who’s pushing for neoliberalism or for achieving anything they use to get elected. Manchin basically ran the party for a while and now he’s a republican.
Elon Musk would be on Kamala Harris’ cabinet, amongst a coalition of rivals. Because the most important thing to do with power is give it to the people you say are ideologically opposed to you. This is why they’re throwing the election to Trump as the most efficient application of this methodology