This is where any linked-up thinking crumbles.

Scale baby, Scale. The fixed costs are amortised over fewer routes so the landing fee has to rise to cover the fixed costs. To reduce the landing fee's you need more flights, to get more flight you need to offer discounted rates to the airlines, at a loss to start. If you did decide to do that the airlines need to fill their planes. Geographically it knackered. Nothing south, few people live to the east of you, so its 20 miles north and west. West you have to travel through a bottleneck of biblical proportions and the alternative is non-existent public transport, which is an expensive train to Cardiff and a bus to the airport (same as most UK airports)

I remember Micheal O'Leary of Ryanair saying that CWL relied on the UK subsidy for keeping that very long runway in good condition as its the first transatlantic emergency landing strip

Its artificially been kept alive, it needed to move to severn junction region 20 years ago when that was first mooted