So, where/who does that money go to?”
Really good question.
I think the answer is, whever the board/management says it should go. The candidate can’t tell it what to do, right? So...if the organizers decide to get behind someone else, they can. So it seems to me....
Most states (and the Feds) have laws that are a variation on the same theme. Candidates cannot use left over money for themselves, but they can donate to other candidates and/or charities.
[So, where/who does that money go to?”]
I believe they get to keep it. Leftover campaign donations supplement a politician’s pension.