I have to disagree with your assessment. This Iowa anon is picking up a lot of nervous chatter from local Dims who are already worried about the caucuses. The establishment is solidly behind Biden because they know the rest of the pack is unacceptable.
No Dim candidate can stand on a stage next to Trump and appear electable to anyone but the most rabid socialist. They will protect and deflect for Biden because he's they're only shot, and a long shot at that.