Norwegian Air recently announced that they're dropping their service to Guadeloupe and Martinique. There was speculation towards the end of last year that the airline was in financial trouble and might not survive, but they've recently raised new funds.
https://www.usatoday.com/story/trav...r-caribbean-flights-not-returning/2849170002/
https://www.recordonline.com/news/20190203/353m-cash-infusion-for-norwegian-air
For me, what helps to balance the cost of the Tradewind flights is to overnight in San Juan. I used to do it for the popovers, lol, but that's not currently an option. I find that if I overnight in San Juan that my flexibility for BOS-SJU flights increases, and that I can find a lower fare on a flight a bit later than crack-of-dawn.
Also, taking the first flight of the day from SJU to SBH is significantly less expensive than the afternoon flights, with savings that exceed the cost of my hotel room. I plan to have breakfast at Le Repaire, drive around for a bit, get my initial grocery shopping done, and just hang out until my villa is available.
Same thing going home. The last flight of the day from SBH to SJU is significantly less expensive than the morning flights which most people take. Again, the savings exceed the cost of my hotel room. I also have more flexibility flying home, and often find a morning flight out of SJU which is less expensive than the afternoon flights.
It also helps that I have flexibility on my time, and that an extra day here and there doesn't really matter.