Bernie won't go

[Proud Liberal Dem]

8. I don't know for sure

But I imagine that they felt that it would be better for him running against the DNC from "the inside" instead of the outside (i.e. Third Party). Also, probably to help keep from inflaming his supporters. However, some of his supporters have so deeply bought into the "DNC rigging" narrative from 2016, they will still reject any outcome other than BS winning the nomination, which is what we're still going to wind up with this year. If Bernie doesn't just drop out, the next best thing is for Joe to ignore him and start running against Trump, like he seems to already be doing. Thankfully, this will almost certainly be the last time we'll have to deal with Bernie being a nominee.