Why is the choice limited to easyJet and Ryanair?

Have you actually looked what BA, bmi, FlyBe actually charge (end price) and compare?

Take the end price .... i.e. after you come home, tot up everything that you actually paid, including food in the airport to make up for the fact that you don't get free food on the plane.

I bet you will find that Ryanair are amongst the most expensive and that BA come very close to easyJet at the end of the day.

Sometimes easy will be cheaper and sometimes BA will be cheaper. I haven't been bmi or FlyBe but I hear their prices can be quite good if you are flexible over the dates you want to fly.