Democrats (DNC) never intended for Biden to be the end candidate.  Biden is a placeholder. The DNC is going to do a swap out at the latest possible moment.  Biden will probably make it to the convention.  Before he is nominated information the DNC is holding will be leaked that proves what we all know, that Biden is suffering server dementia.  It's either that, or he will be arkancided.  Then a candidate who has been waiting in the wings all along, will, like a white knight, under the pretense a reluctant willingness to sacrifice for the good of the country, be declared the replacement candidate. What advantage does this have?  For one, the DNC is already packaging this person.  They are cleaning youtube, twitter, and all social media of any content that can be used against this person, and allowing this person to stage a hero story by planting false information.  Plus by waiting to the last minute to bring person in, they limit the time available to do oppo research.