I would say 3500 pounds (estimation).
But don't forget the wasted time cost (at least 3 h in the airport) based on the pax's cost of time. In addition, blink flights are more flexible, confidential, and can reach destinations that scheduled flights can't.
If you need to go to Sion from LCY, total costs would be very different with the airline.
They are creating pilot jobs, so what is wrong with that ?