The money spent on the Vulcan has been donated by those who want to see the Vulcan fly. Why do people find this so difficult to grasp?
If you want to solicit donations for custom built hangars nobody is stopping you.
The part you find difficult to grasp is that people generally only have so much free cash to give to worthwhile causes annually.
In aviation historical circles the Vulcan has take away quite a bit of that free cash year on year, as people do find it a worthwhile cause.
People are more than welcome to donate to whoever they wish, but generally donations to aviation related good causes in the UK have fallen while the vulcan has been flying.