If your airport has a tiny catchment area then you cannot get the necessary amount of passenger throughput that will enable the prices to come down such as at EMA for example. The natural demand is always going to be less. Bigger airports with larger natural demand are able to offer the airlines better deals hence lower prices.
Smaller catchment area airports like MME and BLK have in the past offered airlines deals to be there but this as we have seen seldom lasts very long and is unsustainable. Doncaster's Manchester owners are currently doing the same and that is why Flybe's base fares are incredibly low. Ridiculously low. It's an artificial airport with a North Western sugar daddy. Look at the domestic passenger figures from this central UK airport they show the true picture. That is why West Yorkshire has been inundated with adverts for this airport. The North West benefits hugely if Yorkshire has too many airports and Yorkshire keeps on suffering.