Because I don’t know you.

Maybe because the investigation naturally led them to Mangione, and everyone claiming he’s been framed are wrong.

Sometimes there’s no conspiracy.

While I’m not sure I agree with everything you said, you’re right that Trump only serves as the useful idiot. If you want to know what’s in store for him, just look what happened to Boris Yeltsin.

Their base is whoever votes in the primaries.

It took about 7 years for the Republican party to change from the Bush/Cheney era to full on fascism. The democratic party is not immune to a drastic change (hopefully towards the opposite end of the spectrum), but it won’t happen overnight and people that want this change must get involved. Money allows to promote an agenda, helps with organizing a campaign, but ultimately it’s the people who vote.

It’s not for liberals to move the democratic party left, it’s for everybody that wants the democratic party to change to do so.