With the way radio is right now and a new owner taking over 1210 AM, nothing is guaranteed
There is as close to a "guarantee" that WPHT will keep within its existing format as is possible to give.
1. There is no "other" format option for an AM station.
2. The station has decent billings.
3. News/talk has always been a cyclical format with constant ups and downs.
4. Advertisers look at averages of several /many books and don't pay particular attention to single book swings.
5. Changing formats causes billing to drop, often to zero. Not a good move for a company that has to show profit growth.