I think it's time to ask if it wouldn't have been better for the DNC to have gotten behind the Sanders camp in hindsight?
That wouldn't have ever happened, because the head of the DNC at the time, Debbie Wasserman-Schultz felt is was Clinton's turn
to be President.
Yes, HClinton was the most experienced and the most qualified, but
she was also very unlikable - as was Donald J Trump.
So the RNC and the DNC thought it a good idea to force voters to chose between two unlikable candidates.
As an aside. In college I worked for the Cheesecake Factory. I opened their fourth store in Canoga Park, CA. At our first training meeting, we were told why
we were hired: We had 10 second likeablity (Meaning, the hiring folks liked us within 10 sec of the interview and it was management's position that the guests would too. )
Likability of the candidate absolutely needs to be a criteria for the DNC in nominating a candidate in the future.