Noctilux's tends to have up's and down's in popularity. It is one of those lenses everybody wants to try - and most Nocti's have gone through more hands than the Stanley Cup! You buy it - marvel at the f1.0 setting and after a while realize that it is a lens that demands that you focus perfectly and, if "analog", know how to focus your enlarger too. No margin of "error"! After a while, most owners sell it and lean back and sigh" Well, I did have one!"
The current hike in price was most likely driven by the "end-run" of it. Buyers flocked to it - thinking they could make a buck down the road.
The idea of the "super fast" lens is appealing and we keep thinking "what pictures could I take with it" - few of us need it. At $3-4000 it is an expensive lesson and a heavy one at that.
Personally I would like to see something like the Canon F1.2 in modern guise, new glass, new coatings and slightly smaller than either the Canon or the Noctilux. Something that could be an all-round 50 without a/ forcing you to take a mortgage and b/ not as heavy to carry. The "signature" could be like the Nocti @ f1.0, with maybe slightly less fall-off in the corners (a bit of tunnel vision at f1.0) but have it "snap" in the smaller apertures. OK, I would settle for a f1.1 or f1.2 as I doubt that I could spot the difference in f0.1 increments! The Noctilux 0.95/50 is probably a good lens (not much has been shown on its performance), but it is big and at $10 000 - no way.
My recommendation is to find one, buy it, use it and if you like it, keep it - BUT if you are planning to re-sell it at some time - gauge the market as Murphy's Law applies here "When you want it - they are pricey, and if you want to sell one - Ebay will be littered with them at a discount".