Yup, this thing is over. Sanders was done even before the pandemic, which just made things worse for him. He can't do rallies anymore, which less important to Biden. Biden can also benefit from the current situation because he's associated with rational leadership.
Sanders 2016 strength was primarily a result of HRC dissatisfaction.
He's currently closer to Biden in the popular vote than he was to Clinton. Biden's lead should expand somewhat obviously but a lot of the biggest and most important states have voted already.
Hardly an indicator at this stage of the race. Sanders won tons of rural counties in MI, IL, MN and elsewhere in 2016. That's what made these states even close. Biden swept these places by fair margins this time around, which is a clear indicator that a substantial part of his 2016 electorate were HRC protest voters and not devoted Sanders supporters. Seems like this also created the narrative rural voters are secret progressives on economic issues. Peak of this hilarious narrative is the assumption WV would be somewhat *competitive* with Sanders as nominee.