It was, indeed, the 787 that killed our 777 BCF's.
We were in the final stages of negotiating for 30+ 777-200's from Singapore Airlines.
Then the 787 test program had that onboard fire, and deliveries kept sliding to the right. Singapore was still willing to do the deal, but kept jacking up the price on the airframes.
About that time Boeing got the new tanker contract, and suddenly got real interested in selling us 767's to keep that line open until the tanker deliveries start in 2017.
The 777 BCF is still a program at Boeing. There will definitely be a market for them, but I think FDX will probably do like Delta did a decade ago - make lots of plans for a giant fleet of 777's, then end up with a bunch more 767's instead....