That could happen. I believe it is a less likely outcome, but still possible, as you suggest.
My key point is that the current Democrat party is infested with Evil leaders and followers. That Evil does not go away, even if the Democrats purge their party of current leaders and influencers.
The Evil does not go away even if the Democrat party does become irrelevant or ceases to exist.
Evil always attempts to transfer somewhere else when it loses its' most effective hosts. Like perhaps to the Republican party. As Lord Acton said, "Power corrupts, and absolute power corrupts absolutely".
We must smash the Democrat party down so hard they cannot rise again for at least 20 years. That will take enormous power. After our triumphant victory, we will find that we then need to keep a careful watch on the Republicans, or whoever is controlling the government.
No victory is forever.