The majority of SI passengers all year round are islanders who need & should get a reliable service.
But are not willing to pay the fares that would mean it would be more reliable.
Any operator in the CI has to sink way way more cancelled flights compared to other areas due wx.
Even though the punters get their cash back and don't get compensation (they wouldn't on the mainland either) the crew and aircraft and all the fixed costs still have to be paid.
All hell would be let loose if a realistic ticket price was given.