A flaw of much of Bernie Twitter’s political thinking is the assumption that the world of Democratic politics revolves around Sanders, and either boosting or stopping him. https://twitter.com/RespectableLaw/status/1247027589279080459

Buttigieg and Klobuchar dropped out because they were going to do very poorly on Super Tuesday, and were running out of money. They endorsed Biden because he was the obvious person for them to endorse, and because they thought it would enhance their political standing.

For much of the campaign, the other campaigns didn’t think about Sanders at all!

They underestimated him, and basically viewed him as a fixed point, gobbling up about ~25% of the vote.