If Biden decides to drop out, or is unable to continue being the candidate, all of the pledged delegates would be committed to him by name, or does his running mate inherit that?
The delegates are free if their specific named candidate is unavailable—both parties.
What did they do when LBJ dropped out?
The rules are weird and complicated. But one thing is for sure. If Biden drops out, Harris would not automatically get his convention delegates. And that’s because in the primaries the candidates run individually, not as a team.
So Harris would on her own. She could hope that delegate free agents vote for her as the Democrat presidential nominee. Or she could hope the new nominee picks her for VP.
That’s my understanding of the process, anyway.