Why is it important that a “national” museum have the type?

Just old fashioned me really, when some of the other Shacks have gone because they had to kept outside or a museum has had to close etc and someone turns around and says ‘hang on why isn’t there one in a British national military aviation museum anyway’.
I really do think that one of the ‘big three’ should have one on display at one of their sites.
Can you imagine the same thing happening with a Vulcan (which saw 15 years less service), the RAF museum has one at Cosford and one at Hendon, plus the IWM has one, all indoors, aswel as all the others in various private museums.

Anyway aside from that is my earlier point, if a museum has a highly relevant aircraft in its collection I personally don’t think that it should get rid simply because it needs restoration, restoration and preservation is an important role.
A prime example for me of what can be achieved is the Hastings at Duxford, another venerable RAF type that gave good service, it was outside for years but then beautifully restored or refinished and moved indoors.

Interesting that the Beverley has been mentioned because I see the getting rid of the Shack as almost the same thing, it smacks of the Vulcan B.1 at Cosford loss, the only surviving complete Canberra B.(I).8 sold by the RAFM to New Zealand, the breaking up of the BA airliner collection, Duxford scrapping the Comet and Samaritan.
I agree that the IWM have gone the best way to ensure its survival, but if they can’t restore it will a hopeful smaller private collection cope, beyond transporting it to a site reassembling it?