I used to travel IOM-LCY on a fairly frequent basis, but the fares are now astronomical (yesterday the cheapest seemed to be just under £190 for a mid-January return flight after the "happy hour" 50% discount was applied!). So Aer Arann no longer get any money from me at all.
Good business? Don't think so; although they would no doubt argue that they used to sell flights too cheaply, they now encourage people like me to look at the Flybe Gatwick alternative.