0 x 77x sold in the past 12 months. 8 x 773 sold in the past 12 months. 2 x 380 sold in the past 12 months. 306 77Xs total order so far, 235 of those are for EK, QR and EY. EK own half the total orders. 319 total orders for the 380. Over half of these for EK.
Airlines do not want to drop this amount of coin on an airframe it seems.
The 773er lacks the legs to carry a useful load longer than 12hr, its payload restricted even on a ADL to DXB! The 77x will improve on this. But Pax will still be loaded like sardines to ensure the seat/mile costs are as advertised. And it is a category F aircraft for takeoff and landing (well anytime the wingtips are not folded). This limits enroute ALTNs. So more ETOPs (or is that LROPs now?)
All three are great aircraft. Orders would suggest that airlines think the cheaper 350s and 787s are a better fit.