Well, we can quibble about the definition of “crazy idea”, I suppose. Use “far-fetched” if you like.
Trump will be primaried, and if he is successfully primaried, (e.g., he loses the nomination for term 2, which is likely if his poll numbers are the same as his approval numbers) THEN you have the scenario where the Dems could actually pick up votes — — but from the Trumpers, not the NeverTrumpers.
I admit I would find it amusing, to say the least, to watch the Democrats welcome with open arms people that the day prior were being called racists and deplorables…….but we’ll see what happens. :-)