Warren would have a good chance for the reasons people have said (able to build a coalition of both moderates and progressives). Bernie always would have been a factional candidate simply unable to appeal to most mainstream Democrats given how his campaign was run.
But, this assumes nobody else runs without Joe in the mix. If Kerry or somebody like that does, possible they win instead.
Also, if most other things go pretty much the same until South Carolina (Buttigieg narrowly wins IA, Bernie narrowly wins NH and more solidly wins NV), it’s possible that Clyburn still endorses someone and that person wins the state, then the establishment/moderate candidates coalesce around whoever that is to stop Bernie. I kinda doubt that would be Buttigieg — maybe Klobuchar? Could even be Warren. Maybe Harris or Booker get more black support in the first place and therefore are still in the race at this point, and one of them ends up as the nominee.
Buttigieg... did better than Warren in South Carolina and Nevada. I know you're not dunking on him but I feel like everybody erases what he accomplished. In all four early states, he did better than Warren did.