GA (light) versus bigger stuff
If you take the most recent pre-recession throughput of GA at COV, say 2007, what you saw was 28K training movements, 5K 'aero club', 7K private and 3K 'air taxi' which must also havve included biz av in COV's case. That's 22K landings. Assume an average revenue of say £20 per landing (use any figure you want but let's be realistic), then that's £440K/annum.
Assuming you'll only get half that traffic for the first few years of picking it up off it's feet then GA will give you just about enough to pay for some tarmac repairs.
Sorry, but there is no way on the planet a facility like COV is sustainable from GA alone - Wellesborne or Wolverhampton, possibly, but you are talking about a massively more demanding infrastructure at COV