An event organizer probably wants to fill booths with people who show up.

I feel for Origins here. I do. As a million dollar show, there are a lot of moving parts, and that is incredibly hard to juggle perfectly. As someone who has both run booths at major conventions, including not only Origins but also GenCon and SDCC, and as someone who has worked for large conventions, not Origins but for SDCC and PAX, this is a known issue and something that is foreseen. Ohio is quite strict about loadin and loadout, and the time frames are there for a very good reason. That said, OP is not a late arrival here. Yes, they missed loadin time, which is going to make their show experience real awkward. But they are physically present at the start of the show being open to attendees, and (more importantly), they preemptively and proactively communicated that fact to their show contact.

If someone just doesn't show up to the con, then Origins should (and does) refill that space with someone else. If someone screws up loadin and doesn't have their booth fully assembled, Origins should not (and when I did work did not) give away that space. It's not certain that Origins screwed up here, because the contracts may have updates since I worked there, and OP may have screwed up in how they tried to communicate, buuuuutttt... It absolutely looks Origins made the mistake here. There should have been someone available for contact 24/7, and as soon as the loadin slot was missed that person should have reached out to OP to get a sitrep. The fact that OP still has a booth, albeit in a different space, is a strong indicator of that as well; the contract for vendors was pretty clear on no shows, and did not provide for an alternate location.

But even without all that clarification that I have first hand experience for this type of situation, Origins is still coming away with egg on their face. A million dollar show needs to have a point of contact reachable at all times, full stop.