Superblue's point was correct though in that the Democrat establishment coalesced around Biden to make sure the centrists had a single candidate. Biden had done very badly in Iowa and New Hampshire. He won South Carolina and then the others dropped out. Before that point, Pete Buttegieg was doing better than Biden.
What would have been interesting, is if Buttegieg had still been ahead of Biden after South Carolina. Would Biden have dropped out and got behind Buttegieg...I doubt it.
I think Biden's win there gave a justification for the Democrat establishment to say to Buttegieg, Klobuchar and co - look Joe's been around a while, he's old and probably won't do two terms - get behind him, let him be the nominee this time and you will be rewarded with senior positions in his administration. Then you can position to be the Democrat nominee in 2024. Bernie and Warren probably won't run then, and the other candidates of the left (Abrams, Gillum) won't have the same profile, AOC will still be under the age threshold to be eligible, so the centrist Democrats can secure their succession for the next decade if they can get Biden elected and then have a cabal of Buttegieg, Klobuchar, Harris, Booker, O'Rourke in senior positions.