As a collector
& user, I think that's a bit of strawman & doesn't really happen that often. As far as "pro" quality, system, RF cameras are concerned, they've
always been relatively expensive, even back in the 1920s & '30s when nobody really collected them. Indeed, once you've taken inflation & average wages, etc., into account, new & used Leicas (or Contaxes, or Canon RFs, or even most Nikon RFs) are more affordable today than they were back in the old days. A good example I would use is the Bell & Howell Foton. It's a fairly rare "collector" camera system, but you can get a working example, w/2" lens, etc., today for about the same nominal price that it retailed for back in 1948, $700 US.
IMHO, what's changed is that because of modern production methods & electronics, there is so much more good quality inexpensive gear available nowadays in the form of autofocus SLRs, point & shoots (which are much capable than their Box Brownie equivalents 50 years ago), & the like, that Leicas seem overpriced in comparison.
Toby said:
My only bugbear with collectors is that they bump up the prices of cameras which limits who can buy them. This means many young photographers would be put off from experimenting with rangefinders, and so limits the new blood entering the RF scene, this in particular is a bad thing.