Option 4: I am not fine with what Trump is going to do, but I am also not fine with what Harris is going to do. And, since Harris said that she wouldn't do anything different than Biden, that could amount to "I am not fine with what Biden has been doing the last four years".

Was that less bad than what Trump has done in one year? Yes. But Trump in his first term was less bad than this, and recency bias means that what we didn't like about Biden was more prominent in our minds.

But my option 4 looks just like your option 2 in terms of how people voted. I'm just saying that the motive may have been different.

To be fair there were primaries, but the DNC only pushed Biden's candidacy. So there really wasn't any other candidates on all the ballots except uncommitted. When he dropped out in July their simply isn't enough time to run a functional primary and campaign for the vote in November. We can't really delay the election to have a primary. The delegates of the DNC do get to vote on who they want and by the time Kamala stepped in she did get the most votes.

It's really a problem of money though. The DNC really are the king makers when it comes to candidates. That and PAC money are the requirements to get a nomination. At least when it comes to presidency. Smaller elections you get more freedom to have a successful without such things. The whole system needs an overhaul unfortunately and I don't see any candidate from any party looking to fix that any time soon.

Biden's hail mary would have been to pick Haley as his running mate, who already had 19% of the Republicans.