For bikes like this I don't know if a museum is such a bad thing. I like vintage racing and I love to see bikes get used on the road, but if they are very unique or irreplaceable historical objects, then maybe preserving them for future generations or as documents of the past is the right thing to do.
This way if someone really wants to race a nsu sportmax, then they will have original ones as documents to copy, which has been done many times. Also if someone wants to know what a famous rider or tuner rode or did in the past, then it is nice to be able to look at the engines and motorcycles they left behind preferably in original condition.
I have a few old semi-famous racing Nortons, Heinz Kegler's works Daytona racer and Reg Pridmore's championship winning Manx, and I believe it is my duty to preserve as much of their history with their past owner's as possible. If I want to go riding or racing I will do it on a bitza or replica with no historical significance.
Benjamin