Edit: oh yes, and a twin longer than the 748! appears a bit foolish to make one of your flagship aircraft obsolete...
The 747-8 still carries ~65 more paying passengers than the 777-9X, ~465 vs. ~400 - and can go a bit further fully loaded to boot.
Things are not quite as bleak for the 747-8 as that article suggests. Yes, there are 747-8s sitting on Paine Field that the customers don't want to take. What it doesn't say is, the customers don't want their airplanes until they can get the GEnx-2B PIP engines (Product Improvement Package). The PIP provides a significant improvement in fuel burn (I don't know if I can state how much, but we exceeded expectations). Those airplanes will deliver as soon as practical after we get the PIP certified. Of course, that's sort of on hold since the FAA is on furlough due to the budget impasse
While air-freight is soft right now, that'll eventually recover, and if you want a freighter that can carry more than ~100 tons, the 747 is the only game in town (~140 tons for the -8). Further, the 747-8 has a substantial ton-mile operating cost advantage over older 747s.
Boeing and GE are not ready to give up on the 747-8, in addition to the tens (hundreds?) of millions that when into the PIP engine, Boeing is continuing to work on future package of weight and drag improvements.
Given "typical" 3 class arrangements (I wonder just exactly what that means, but bear with me), we have:
777-9 ~ 400 seats
747-8 ~ 465 seats
A380 ~ 520 seats
It would seem the 747 still fills a hole between the 777 and the A380.
The business case for the 747-8 never expected it to be as big a seller as the 747-400 (roughly half of all 747s built were -400 models - a success that I don't think Boeing expected). The question is, will the -8 be successful enough to make that investment worthwhile.
Jury is still out on that part.