BEagle, that's a good question. Ignoring the LoCo carriers ex-JER, BA finds it worth doing 5-a-day to LGW. Many of those pax actually want to use LHR for l/h travel, so there is certainly some demand for a JER-LHR link.
BMI dumped the route a few years ago [the day after I booked it, as it happens] ... but I have no doubt the reason is the relative value of the LHR slots, which could earn more being used for more profitable routes.
As to NHT ... fantasy land, IMO. I shall continue schlepping between LGW and LHR, although cheaper fares can be found ex-DUB, so there are other ways of skinning a transatlantic cat [once you get to DUB]
