It never ceases to amaze me how much DL is trying to build up BOS when the market is already super oversaturared and it serves no purpose in its network.
BOS is a very wealthy market which is growing and there's a higher than average propensity to travel for the population in the region. Moreover, Boston punches above its weight for international travel thanks to the industries (finance, biotech, information tech, education, health care) which drive the local economy. It's also logical for them to get as big as they can at BOS since there's little room to expand the airport's footprint and pushing WN out of Terminal A keeps B6 from taking those gates down the road.
Longer term, it's unlikely that B6 stays independent, and being the leading legacy carrier at BOS is good strategically in the event that B6 is involved in consolidation. If WN buys B6, they have an obvious niche as the only full-service carrier with a BOS hub. If AA or UA were to buy B6 (unlikely IMO), both carriers have a history of retrenchment at BOS (which DL also has) and neither has shown great interest recently in point-to-point service in non-hub markets. In a consolidation with AS, it's not clear that AS would want to continue with products like Mint and the AS brand isn't well-known in Boston.
Also if I'm not mistaken this will mark the first time a US airline flies to LGW since 2007, assuming of course DL actually does choose to fly there.
The last U.S. carrier to serve Gatwick was US Airways, which ended its LGW service in late March, 2013.
I flew DL from Boston to Gatwick a few times in the months following 9-11. The loads got as low as 19 on one of my flights.
Loads were low on everything post-9/11. The economy was cratering thanks to the post-dot-com bust and people were scared to get on airplanes.
Why does everyone think LGW doesn't get any business traffic ? Just try coming off a flight from the US and heading for the Financial City area of London on public transport like trains using LGW instead of LHR and I'll think you'll find LGW wins 9 times out of 10.
Um, because the carriers who have access to the traffic numbers have found there's little demand? U.S.A.-LGW is a pretty obvious niche to try. And if you're paying several thousands of dollars or pounds round-trip on a business class seat, what's another hundred or so on a black car to/from Heathrow?