I think Warren would've made the best president of the bunch, but looking at Biden's results, pretty sure she loses. She was always a bet that Trump had made himself so unelectable that the Dems really could swing more for the ideal than the electable, and that just wasn't true based on the vote Trump ended up getting.
I'm a bit less certain on Bernie, but I'd lean towards he also loses. He would have to make up a lot of votes to counter all the lapsed Republican suburbanites Biden managed to pull against Trump, most of whom would probably never pull the lever for Bernie.
You could look to young voters, but Bernie was never able to get a turnout surge from them in the primary, so it seems very hopeful to think he could've gotten it in the general. You could look to him poaching some number of anti-establishment blue-collar whites from Trump, but again, looking at the primary, Bernie's working-class white support evaporated pretty quickly against Biden, so it really starts to feel like Bernie's rep as a Rust Belt whisperer was just an illusion from running against Hillary. You could point to Biden's underwhelming Black turnout, but hard to see how Bernie fixes that when Biden trounced him in the Black vote. The best path is Bernie really did cream Biden in the Hispanic vote in the primary, but of the close states that Biden won through suburban votes, it seems like Arizona is the only one where that maybe gives you a road to make up the Biden votes you'd be losing.
Bernie almost certainly loses Georgia, and AZ/WI/PA would all seem to be at risk. And any heavily Hispanic states Biden lost seem equally out of reach for Bernie. Bernie probably does even worse with Florida Hispanics because of the socialist taboo among Cubans, and while maybe he could've reversed some of the weird disaster in Texas' Rio Grande Valley, it would've come at the cost of huge losses in way more populous areas in suburban Dallas and Houston.
I feel like alot of posts in this thread forget that Bernie was killing it early on and was the clear front runner after winning Nevada. It wasn't until all the other moderates started dropping out and endorsing Biden did Bernie's numbers start to falter a bit. Virginia was the big "Oh Biden has this" moment but I still think Bernie stood a chance after Virginia but covid was getting worse at the time and Bernie's campaign was receiving heavy criticism for not concedeing cause of covid. I think Bernie could have taken it to the convention.
Bernie's numbers didn't really falter though. He was always winning with ~30% of the vote against a divided field. Nevada was his best at 40%, which has its own weirdness since it's one of the last remaining caucus states. It was always a bet that he could win with a minority so long as the opposition was split, and there really wasn't a strategy for what to do if the moderates actually did coalesce behind a single candidate. That same 30-40% that could win in Nevada and feel like he was killing it against a half dozen challengers didn't mean much when Biden could reliably pull 60% to himself without the others distracting.
