I suspect it's probably too late for the Democrats to switch horses now, but I hope that this finally pile-drives some smidgen of a lesson into them that they need to actually try to win elections rather than just assume that since they're not crazy or evil like the Republican candidates people will naturally prefer them. They need to pick candidates that the people like and put in the effort to run those candidates well.
There's still five months until the election, there's plenty that Biden can do between now and then to show people that he's a good choice. And then maybe this time once it's all over the Democratic Party can do a major rethink of what exactly they're doing with all this. Like they should have the last time they ran a candidate against Trump that they thought simply "deserved" to win.