I spend a fair bit of time trying to estimate the feasibility of air services between city pairs. One of the first things to establish is the population contained within the natural catchments of both airports concerned. The demographics of those populations are also important.
As OXF is fairly central within the county of Oxfordshire it's probably reasonable to say that the county's population roughly forms its natural catchment, this being 635,000 souls with Oxford comprising 152,000 of that number. I haven't looked at the demographics but I would guess that per capita income is above the national average and that the professions rank highly among the employment figures.
Taking the above into account I would think that the potential may exist for an OXF-EDI double daily air service. One of the biggest hurdles is making the potential market in Oxfordshire aware that such a service is being launched and one of the first questions I ask any airport with similar ambitions is "How much are you prepared to spend in the first 12 months on marketing/promotion of the service?". Perhaps in this particular case the answer was "Not much" if reports of poor marketing are correct.
The above thoughts certainly aren't a detailed analysis of the potential for success, and I haven't even mentioned the type of equipment the route might need to be successful, but I wouldn't dismiss its possibilities out of hand as some posting here seem so keen to do.