You bring up an interesting point...if the convention is thrown into an open situation...I think most Bernie-supporters and half of the Joe-supporters would NOT go along with the scripted change. But they’ve angled themselves into a corner...they want a serious contender for President, to really oppose Trump (instead of just picking a good loser (Jeb-type)).
What if they use the virus situation somehow to fail to complete the Primary elections. Then they could go straight to that 2nd ballot.
Except that the AOC wing stands to gain one hell of an improved position if they run their own ticket and it beats the Democrat nominees.
How could the socialists win without being part of the Democrat Party? If the Democrats keep on the path they are following.