Nice sentiment. However, if your figures are right, and I have no reason to doubt them, that's a lot of money for 8 flights a week to London, and a handful to Liverpool, Prestwick and Birmingham.
A complete change in the attitudes of people in the NW to THEIR airport is required for anything to improve. As the former CE of Ilex said "Derry suffers from a lack of civic pride". Too true. Both the cleaning bill, and the underutilisation of the airport are evidence for this.
More fundamentally, as I said before, Derry airport putting all its eggs in the Ryanair basket was probably a bad idea. A carrier with smaller planes would no doubt have more routes with better frequencies.