This constant 'if so many people donated so much etc' really has been done to death by now, and in truth, I have posted the same thing myself in the past.
It becomes increasingly apparent that that sort of thing is simply not going to happen, for people are notoriously bad at putting their hands in their pockets. Having seen it, they are probably satisfied, and not necessarily interested in seeing it again, at their expense.
I saw it at Duxford, earlier this year. and. whilst agreeing that 'the Vulcan has delighted 1.5 million people at Airshows this year', a lot of them were 'delighted' simply because they were at the show anyway. At Duxford, after it's display, obviously very muted compared to it's RAF displays, for various reasons, I overheard several people, my wife included, who were questioning what all the fuss was about as regards this aircraft.
It seems to me [an enthusiast] that the only people interested in the Vulcan are enthusiasts, not the general public, and those of us who have seen it are no longer prepared to finance it. Nothing lasts for ever.