<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by NM:
It was never going to be economical to have two engine manufacturers competing for the 100K+ thrust requirements. The development costs would not be recovered for both and that would increase the overall cost of the aircraft purchase, making the 777 less competative against its rivals (A330, A340), which is why Boeing wanted a single exclusve engine supplier in order to keep the supply cost low.</font>
There was another reason, too. GE (through GE Capital) was to finance a lot of Boeing's development costs, almost certainly at a very favourable rate.
All the relevant factors (including, one suspects, a certain amount of keeping it within the USA family) led to a decision which was certainly a rational one at the time whether any of us would have decided differently. It's just that history hasn't worked out well for Boeing on this one, which leads to (I think justifiable) speculation as to whether it might yet change its mind.
ConcordeBoy, did the e-mail say whether it would be R-R who would be in breach of contract, or just Boeing? If it would be just Boeing, surely that would only be the GE-exclusivity deal. Faced with a choice between zero sales (through project cancellation) and a chance of some sales even if in competition with a Trent, GE might yet decide to abandon reliance on that deal and allow R-R a chance to get on board. If R-R could make a business case, of course.