i mean bristol got CO for a start and id hardly call bristol superior to NEMA for long haul with its tiny 757 only runway in comparison
I suppose as long as an airport can physically cope with a route (and apparently BRS can with CO to EWR) it is all down to commercial considerations.
The south west has the second strongest economy of any region outside London per capita GDP, and Greater Bristol provides 25% of the south west's GDP. There is also an above average number of ABC 1s using Bristol Airport.
Forget Bristol being a smallish to medium sized city of 400,000. That is the city population, kept within a restricted municipal boundary for purely party political reasons. The urban sprawl actually numbers closer to 700,000 with the satellite towns pushing it up even further to around one million people living within ½ hour's drive of the city centre.
Chuck in the well-off of the Cotswolds, Bath and Somerset, plus those from further afield who regard BRS as their local airport and you might begin to see why CO view BRS as a likely winner.
Now NEMA might have all these things as well. I don't know. If it has perhaps the airport management should be looked at.