The whole thing is spirit avoided rebuilding bwi to its prior glory in order to make MIA work. The problem was going from zero flights to 31 cities and 50ish flight per day in an unproven market, and it turns out it was a really bad idea. While BWI market was rebounding, F9 was adding flights NK stopped doing and couldnt get back into due to attrition and MIA. Spirit finally figures out MIA operation was a loser, and no bread and butter to redeploy, cuz Frontier does it now. And the second spirit bailed on MIA intl routes, F9 jumped on it. And now F9 going after SJU. I think Spirit's network planners finally getting the hint the they are getting owned by F9 and are at least going to try and fight for SJU.