I also thought Biden would have faded as he did the last two times he tried. It has been a lesson to me how much being VP can help an otherwise completely uninspiring candidate.

Bernie’s support is actually much stonger than Biden’s. IIRC, over 70% (72%?) of Bernie’s supporters would not switch to another candidate (I am one), while “only” 55–57% will not switch from Biden (quotes on “only” because that is still a very nice number for him).

The important numbers are in the early states, where people have started to pay attention. Biden has fallen in Iowa to as low as 4th (I think he is higher right now), 2nd or 3rd in NH, tied for 1st with Bernie in NV, and has lost his double-digit lead over Bernie in SC. Six months ago Biden was crushing Bernie everywhere except NH.

As we saw in 2016, Bernie brings out new voters. This means he will overperform the polls as he did in 2016, despite the massive election fraud by the DNC/Clinton campaign (one and the same in 2016). Based on that it is quite possible he will win all three of the first states. That will change the dynamics for SC and set Bernie up very well in CA, where he is already leading.