Danny,
So if you own a corner shop, with your wife and family to support, with a supermarket only a limited distance away, are you going to sell your goods at such levels, just to make your shop look busy, whereas you can't afford to support yourself and your family, or are you likely to explain that you are offering reasonable prices and if 'you' don't like it them please shop elsewhere?
Point being PF, airlines now expect the lowest possible costs to use an airport, just look to Ryanair's business model to see that, if CWL are not prepared to lower their costs while other airports are, it doesn't take a genius to see why CWL isnt attracting new airline customers.
Airports can make revenue from other sources bar aircraft, such as car parking etc, however without the added passengers that the airlines bring that won't happen.
Those in this thread wondering why no other airlines have come in, it looks like the fees could be a factor.