Scandinavia.
It would wouldn't it.
Jabird.
I find the word 'plebs' offensive. By your inference, are you suggesting that anyone who is a BA Economy class pax. a 'pleb'?
At 4,900', LCY is too short to do JFK direct but 6-7,000' would easily oblige. How many seats does the A319 on the BA001?
An all J/F class 757 with 100 seats leaving JFK/BOS/EWR/IAD at 1900L (0000 Z) would arrive in LHR/STN/LTN/LGW or wherever the owning airline's target customer base wanted to, at around 06-0700L. Going westbound, leaving London at 0800 L, it would get in to the US at around 10-1100L.
I don't know how long the tech. stop in SNN is but I would say around an hour & an A319 cruises at say, M0.74-76.
A 100-120 seat 757 could probably go from any of the London area airports (& I include Farnborough & Biggin Hill) non-stop to the eastern US at around M0.77-0.8 saving sector & turnaround time.
Any airline, if it was to operate such a route, would have to conduct through research to find out its clients needs. And careful negotiation to have a dedicated departure/arrival terminal ex-UK to satisfy the US Port of Entry requirements on offer in The Irish Republic.