Crazy that 777 prototypes were sold, but they just couldn't sell any of the 787 prototypes (#4 is a test plane, #5 was already scrapped).
I think it's worth noting as well when calling this frame (specifically, WA001) the prototype is that Boeing always intended from the get-go that it would be a customer-deliverable aircraft rather than a traditional prototype. There was a similar intent with the 787 but the amount of rework required far exceeded that which was reasonable.
IIRC Airbus followed a similar route, though slightly more conservative, route with the A380 - the first full frame was never meant to be deliverable, but the subsequent four were after completion of the testing programme.
Amazing that the A-model 777-200 can actually fly from Hong Kong to Tucson non-stop when it's empty.
I mean, without passengers and cargo you're always going to get a lot further than otherwise. HKG-DMA is 7661 mi GC, which is an impressive extension over the paper range, but not that far detached from QF sending their retired B763ERs SYD-VCV non-stop, and of course the non-stop LHR-SYD delivery flight for their first B744 that was nearly 3000 km further than paper range (though they did cheat on a points).