Going Boeing,
That's been my thinking - but that line in the article made me wonder.
Seattle has been under pressure for a while to stretch the 787 into the -10 but this would clearly cut into what is now a major cash producer for Boeing (the costs of the 'core' models having been amortised years ago). A 787-10 would rip the guts out of the newer LR 777 derivs (which are yet to break even).
Likewise at the other end - Boeing will have to replace the 737 at some stage - but who would want to p!55 off the likes of Herb and O'Leary by suddenly killing the residual value of the hundreds of new airframes they've invested in? That said, the pressure will build - AA said very recently that they'd like to replace their MD80s with 738s, but will wait to see what any single-aisle son-of-Dreamliner looks like.