Well in my postulation biden would step down next year OR choose to only do one term and harris would step in. If he retires in 22 harris automatically becomes president and as the incumbant I don't think anyone would run against her in 24. If joe does one full term and she decides to run in 24 she has the inside track automatically. So the race for the DNC is hers to lose in 2024.
As for Haley...who knew trump wouldn't go away..LOL...she bitched up to him completely. BUT if he were to say drop dead or get convicted of whatever NY prosecutors can find then the field is wide open and she DID signal she's interested in running...
So its NOT SOO implausible.