1. Hunter Biden's Ukrainian business dealing would have been found out and publicized anyway.
2. Bloomberg would have pushed Biden to the side sooner or later with or without Trump's impeachment.
Maybe, but later would have been better since it would not have given Bernie as much of an opening. With Biden collapsing so soon, Bernie easily has the momentum to win it, and then Nixon vs McGovern will happen all over again.
Second, I doubt Bloomberg will stop him either; the left will force him to apologize for stop and frisk, castrating him before he even gets out of the gate. If he does not do this, he has no chance of winning the primary. But if he does, he can't run on his record of making NYC safer since stop and frisk was a major part of that. He will then be left with pretty much nothing to run on. He has truly been put in a Catch 22 by the woke Dems.
Even so, I still don't think that if Bloomberg plays everything right he can win. Biden will stay in this race until after he looses in SC. Though he is doing poorly, he still has a lot of name recognition and will suck the oxygen out the moderate lane, prevent the moderates from consolidating. You may think this gets better after Biden drops out, but that is when Bloomberg comes in and will do the same thing. Meanwhile, Bernie has consolidated the radical wing of the party and will continue to win pluralities, albeit not majorities.
The only hope is that both Biden and Warren drop out now and push their supporters to Amy Klobuchar so she can consolidate the moderate wing before Bloomberg comes into the race. Even so, this is still a slim hope. Trump had 130K people in NH come out to vote for him in an incumbent primary (largest ever in the state by an very large margin) while having a 95% approval rating in the republican party. It was a foregone conclusion Trump would win the primary, which means there is no reason to show up and vote unless you are incredibly enthused. Meanwhile, the Dems are struggling to get 2016 turn out numbers for a primary that is not an incumbency.
PS, an Obama endorsement of Klobuchar would be necessary as well.