Magellan, i really don't get the point you're trying to make about the tax. It's payable regardless of whether the person is aware of it or not. No-one is going to pay extra for a flight just because they know that the extra is tax. it's the final price that matters and that is what everyone is always going to compare.
And last time I looked, there were more routes on offer than just Southend. Good luck taking a train to Dublin and Belfast.
Lets not forget that the new terminal was built at minimum cost, so operating costs are not going to be all that high. Most will be offset by the Stobart offices anyway. Combined with rental income from the logistics hub and the proposed industrial development on site, then the airport will be doing just fine.