What would a full on progressive Dem party look like? What would map margins be if the party went that route in 2022?
Even when I was active in the DNC - and that was ages ago, back in a
very different political climate - the progressives were seen, at best, as useful idiots by the establishment and at worst, political liabilities that had to be controlled. And this was during a time period where they
weren't all cut from the same cloth as the DSA. I'll tell you about what they were like back then some other time; it's not important right now. What is is is that there was an active and ongoing attempt to keep them backing Dems that by all accounts, the Progressives wanted nothing to do with, but they were essentially forced to back via the magic of "vote more and better Democrats."
Which is fucking rich, when you remember that Joe Lieberman was active during this time, but that's a story for another thread.
The Progressives in their current incarnation are political poison. While they have rabid support in their base, this base is incredibly small - just really good at being loud, their actual policies are wildly unpopular, and while they pretend otherwise, they fucking know it. This actually is responsible for a lot of their behavior that you can see in action: Aggressive narrative control, relying on their base to browbeat people with the message, and using agitators to justify getting what they want when they can't get a mandate (which is most of the time). The modern Progressives have no respect for the political process; they are as despicable in victory as they are vitriolic in defeat. If they get what they want, it's good, no matter how many people suffer along the way and how hard.
The only place Progressives can really dominate politically are in the purest of blue-state strongholds (and even there, they often wind up being fucking hated when their policies result in disaster). Red states will flat-out not take them, and even blue states familiar with their policies resoundingly hate them.
Going full Prog would basically doom the party to doing about as well as the Greens.