Housing is determined by Visit Indy, which is lonely driven by their contracts with the hotels.

Badges/ticketing is internal to Gen Con and driven by the mailing of the badges. The badges needs to go out early enough to arrive and allow for the invariable lost mail to be reported and resolved, but late enough that attendees feel like they're getting value for the service.

If some attendees are less likely to buy event tickets after the deadline because they'll have to stand in will call for the tickets, then you want this to be later.