How fragile is the IOM network at present?
I think you've hit it in one Tonyq. Since the last time BA decided to stop service to LCY and were eventually convinced through financial incentives to come back I personally have been a bit nervous about stability of the services we have on hand and the resultant impact on local business. I'm almost surprised Flybe are still around and easyJet will, as you say, pull up anchor very quickly if it suits their purposes. In truth, BA provide the only 'real' airline services if one wants to go further than simply point A to point B on a single ticket. Contrast that with what is available in Jersey, for example.
I think one very real problem is the lack of government involvement; as though this essential part of our infrastructure is wholly unimportant. I have seen numerous airport owners decline to allow competition in where it is clear existing services would be cannibalised. That the IOM Government can't do the same on what is essentially a national rather than simply an airport basis is deplorable. That, at least, would give carriers some sense of comfort as to whether it is worthwhile to invest a pot full of money developing routes for a population of 80,000 without the likelihood of some predator carrier coming in to steal the investment.