that was actually just a question of time, and the situation in US was just the trigger.
I spoke around one year ago with an Irish guy at the Loft (usual meeting place pub for irish and Ericsson people in stockholm) that was sent here by AA to reorganize the business here.For instance moving out the AA office from the city center and other cutcosts. He told me clearly that the 4 flights out of ARN:AA to ORD, DL to JFK and SK to EWR/ORD were too many for the swedish market. AA was staying there due to big corporate customers as Ericsson and the traffic to the Kista mobile valley. We got in between the Ericsson problems, the explosion of IT bubble, the slow but continuous devaluation of the swedish crown (around 20% in 2 years compared to the US$)that cost any visit to the US a fortune. A bigmac is probably cheaper now in stockholm, and for people knowing sweden, it was not a cheap place.
To sum up, the bombings just accelerate a process that was due to arrive sooner or later.
Probably the analysis is the same for DL.