If I were one of Bernie's supporters, I would lose interest and fade away. There is just nothing Joe Biden brings to any table I sit at. I think the argument that Joe Biden is more likely to beat Trump than Bernie is not only incorrect but the wrong way to approach the election.
This election is not about the Dems, it's a referendum on Donald Trump. He either wins with support from his uner-informed marginalized base and independents, or he doesn't. Who the Democrats run against him is largely beside the point. If voters want to dump Trump they will, in which case if the Democrats nominated Bad Bunny, Bad Bunny would be elected. (No offense meant to Bad Bunny who I think is great).
Many states, including a few big ones, haven't yet voted. The coronavirus may turn things on its head. The youth vote is not turning out. Bernie can help with that.
I think it's admirable of Bernie Sanders to stay in the race long enough to try and guide his flock over to Biden to beat Trump. I'm counting on anti-trumpers to dump Trump, not Joe Biden.
Update: Admittedly, I know nothing about the details of climate change. But Joe Biden just said he wants to take millions of cars off the streets. Really? What happens to the auto industry then, and particularly its workers? From those who work in the manufacturing plants to those who work in service departments at car and truck dealerships and those independently employed as mechanics? Memo to Joe Biden: Keep your hands off my car. Especially this week when riding mass transit increases your risk of exposure to the coronavirus.
Update: Bernie mentions how the world looks to the U.S. for democracy and leadership. That may be changing thanks to Donald Trump. Check out this opinion piece from the South China Post about how Asia will have to go its own way if it wants to be democratic, because the U.S. has dropped the ball. Our standing in the world will take a decade or more to repair -- far longer than any one presidential term, be it Biden or Bernie.