The Northwest driveouts right now are for the same reason as to FL. Short but intense summer season in Seattle/Oregon, but getting cold now, and Phoenix, Las Vegas et. al. remain warm.
FL driveouts almost never happen in the fall. They're buying new cars in south FL, waiting for hurrican season to end and the winter rush to begin. Once in a rare while one such brand new car with FL plates will show up at one of the local rental lots in NY, for an exorbitant one-way price with the previous customer, according to the counter agent. Drive in, yes. "Reasonable" one-way rates out, perhaps rarely, but not officially a driveout.