My guess is that the costs for a carrier of intermittent and low revenue services will cause accountants to blench.
Originally, a company might sustain narrow margins on a route, in order to still carry pax and hope to carry them to other destinations. That is, your service would be so good - your customers would love you.
Nowadays, it is often case (not always) that each service must stand by itself and that means the 'death of a thousand cuts' as we saw with so many other carriers and companies in other fields.
Or, perhaps the deal with Ezy was to hand over all their routes to IoM? We shall never know but, I for one, am irritated to now have to go all the way to LGW.