The question isn't so much will the world be ready for the Blunderbus in 2006. But rather will the demand be there over the 30-40+ year life of the programme. It's also a long term programme after all.
Boeing bet the company on the 747 and I understand the programme didn't recoup the investment until the 744 came along. The world certainly wasn't ready for the 747 in 1969. Intially the aircraft was a bit of a millstone (and a bit of a dog apparently early 100s were slower in the climb than 340-300s).
Argueably, over ordering 747s was the beginning of Pan Am's long slow decline (hands up who remembers riding in mostly empty 747s in the early 70s?). By the late mid 80s the market was more than ready indeed demanded bigger, longer range ones. Boeing responded and the sales figures went through the roof (I think I right in saying the Boeing have flogged more -400s than 1,2 and 300s put together).
Point two:If you draw a line from Wilbur and Orville and extend it to today the compound growth in the number of people travelling by air is about 5% it is reasonable to assume that this will continue - which means a doubling of pax numbers in 15 years and triple today's figures 5 years after that. Put it another way, a route that will support 3 x 744s by carrier A per day in 2006 is in all likelyhood going to support 3 x 380s daily in the 2012 to 2015 timeframe and considerably more than that by the mid life part of the programme say by 2021-2026.
Ref the sonic cruiser. I could never figure that one out everything I've read has said that drag increases dramatically in the transonic region say .92 to 1.2 (which is why Concordes used afterburners in the acceleration phase only out to about M1.5 they didn't need em after that).
So I always thought that something that was meant to cruise at .97-.98 would pick up a heavy drag penalty not to mention the fuel burn needed to get above the slower traffic early in the cruise (no point being abole to go that quick if you are stuck behind an A340 eh?)
I could be wrong (no change there then) but maybe that's why no body actually wanted it... and nobody actually wanting it maybe why Boeing binned it