STN was reduced because of cuts at STN. Out of the rest LPL has always performed well.
I'm not going to second-guess RYR's logic. Their recent withdrawal from BHD shows they have their very own brand of this.
Still, I have no doubt a reintroduction of double-daily STN would work, as would daily LPL.
I doubt RYR would pull out of LDY because of BB (and let's face it, if they've stuck it out at Derry this long, then it seems they will for a while yet), and I also doubt DCC would allow any action by BB to jeopardise the major carrier at the airport.