I'd say "The Onion" part of this is that the democratic party doesn't need to learn any lessons because it's doing exactly what they want to do. The people who will refuse to learn from this are the people who still put faith in them and the democratic system in general.

Sure democrats would prefer to win but the most important thing to them is making sure that policies to the left of the republican party are never a serious threat to the donors they both share. That's pretty obvious at this point, right?