o restore this cathedral will take some crafts that arent even practiced anymore.
That's not really correct: a Dombauhütte
(cathedral building workshop) was originally established to build a cathedral here in Germany (and many other parts of Europe), nowadays doing the repairs and reconstructions.
The largest (and perhaps best) in my state is the one in Cologne, with 30 stonemasons and sculptors, about 16 glass painters, glass artists and glass restorers, numerous scaffolders, roofers, Carpenter, painter, electrician as well as a locksmith and a blacksmith. All together about 70 persons (without the academical and administrative staff).
The one in our district town is smaller (it's not a cathedral, but the Wiesenkirche [St. Mary’s in the Meadows, 1313 AD] is one of the most magnificent late Gothic hall churches in the whole of Germany), however with a nice website in English: Mason's lodge Wiesenkirche Soest