I am assuming that is because most 787 operators are 'full service' airlines rather than budget carriers, who generally run cheaper or second hand 737s or A320s

I am assuming that is because most 787 operators are 'full service' airlines rather than budget carriers, who generally run cheaper or second hand 737s or A320s. Then again, I just came back from Europe in a Scoot 787. Scoot are the 'budget' arm of Singapore Airlines, but I guess with the wealth of Singapore, their budget carrier is the equivalent of most other full service carriers.