What is your basis for that?
These group aren't stupid.
They won't be impressed with a party that ‘gives’ them the vote then takes it back if they make the wrong choice: the wrong' choice is 'anti-elite Bernie. Clinton was the Establishment choice and she's being rejected.
An 'anti-elite revolution' going on - and it's happening in both parties. Biden's an establishment elite. He doesn't have a chance. He'd do worse than Hillary.