I think that's the point of the comment you replied to. Biden did quite badly early on in the primaries, and only after a large chunk of other candidates dropped out and threw their weight behind him with endorsements that he did significantly better. In a sense, the party has made up its mind on the candidate it wants.
By 'quite badly early on in the primaries' you mean the first two where Pete won one and then tied Bernie in the state next to Bernie's home state, and then one that Bernie won, right? After that was South Carolina where Joe won handily, then Super Tuesday where Joe basically ran the table and never looked back.
The party did not decide, the people clearly indicated who they wanted. They wanted the person who could win the general election. Turns out they were a lot smarter than you give them credit.
