To tie this to Leicas, I would ask whether Leicas are in very limited supply, but very high demand?
Well, they are nowhere as limited in supply as an exotic violin. But there is considerable demand for the ones out there. Perhaps that explains the prices they command in the used market space.
Do competing or new brands perform just as well?
By what measure? The pictures, in handling, intuitive use, access and operation of controls, durability, social statement, pride of ownership, retained value? Some newer cameras may perform better by some measures, but probably not all.
Can people generally tell little or no difference looking at photos by Leicas vs other good cameras?
This is probably true. A good imagemaker's images will come through no matter what tools he uses. A cheap Fed or Zorki with a good Zeiss copy lens just might work splendidly in his capable hands. Likewise, a poet can write a poem with a five cent pencil or with an $850 Montblanc 149. The message will come through. He might like using that nice pen better, however.
Are materials or engineering significantly better than other makes?
Maybe not altogether better materials. I have read that the creator of the first Canon copy of a Leica was taken aback by the fact that there were no exotic materials in the Leica of that time (early 1930s). And he set out to make an equally good clone of that camera for less. I understand that Canon missed the mark by not getting the thread pitch exactly right. IIRC, the Leica of the time had an English system derived thread pitch of 25 tpi which was close, but not exactly 1 thread per mm (25.4 tpi). But that early Canon probably was comparable to the Leica of which it was greatly a copy.
Engineering may be better with the Leica M by reason of the fact that it is well conceived and not loaded down with useless "features" that can get in the way of one who actually knows how to use a camera. Fit, finish, and smoothness and relative quietness of the shutter put it above many me-too cameras, IMO.
I would be interested in the opinions of users of Zeiss Ikon's M body who may be Members here. That Cosina camera looks to have lots of M-like culture to it, maybe even surpassing the M in some ways.
