Normally when people lose elections, they do a campaign autopsy where they examine the Whys and prepare for the next run. Bernie never did this. When you look back at 2016, he lost for many reasons but a major issue was pretty simple. In American politics, the most important area of the country is the south...for different reasons. For republicans, the south is a delegate-rich area where you're forced to appeal to the base of the party (rural whites, religious voters, etc). For democrats, the south is also a delegate-rich area where you're forced to appeal to the base of the party...black voters.
Bernie had zero plan to appeal to those voters in 2016. He basically ceded the area to Clinton, and by the time she was finished collecting delegates there her lead was nearly mathematically insurmountable. Four years later, surely Bernie had a plan to combat this right? Nope. He did nothing to combat this. Similar to his policy/budget ideas, his campaign was built entirely on magic: young people are going to turn out in mass and neutralize any coalition or demographic opposed to the movement. Well...that didn't happen, again. And with no plan B, Bernie was left shyt outta luck.
This leads into the other big problem: his campaign was built on the premise that he could win the nomination while getting 30% of the vote. A large field of moderates would split the 70% and by the time 1-2 challengers remained Bernie would win California and perhaps double his delegate lead. That was literally the plan. It didn't work. And once it didn't work...again, he was left with no plan B. Same shyt happened to Hillary in 2008. She focused entirely on the big states, figuring that California would double her lead and thus make her the inevitable winner. Instead, some guy with a funny name and his campaign (who understood math and how delegates work) ruined the plot...and she ended up being mathematically eliminated shortly after Super Tuesday. BTW do you know who decided not to hire Obama's delegate/math/etc guys? Bernie Sanders.
