If the Dems had just stuck to their (stated) principles and not allowed themselves to be pulled so far to the right as to effectively be moderate Republicans, they could hold onto power as long as they wanted.

To your point - people don't vote for "meh" - they vote for someone who inspires them. Biden won simply b/c "he's not trump" and that sentiment won't carry the midterms. Dems - follow through now, and give people more than hope to get them out to vote.