f, your guess arrives in less than 12 months.
I doubt demand for Leica R is driven by much more than a belated recognition of the quality they deliver, and the special character they imbue in images, M lenses are a limit case after all, and the company put their heart into the R range as well...the adaptor/mount market has facilitated this, along with the web, and better sensors of course - blame Sony! Video demand plays a part, but prices will always rise for a limited volume of high end lenses, each year more get dropped, damaged, lost..
Makes you wonder what would have happened to CY prices if Zeiss chose to ignore the DLSR market as Leica have. The 21mm Distagon is 20 years old, and fetches the same money as the current ZE model. Several of mine cost $1000 or more. Some of the newer ZEs are great already, the 135/2, 15/2.8
Prices also come and go in shorter cycles within the long term trend, and when people realise how poor the new M is for Leica R lenses, the less well-known ones will maybe fall somewhat. Then there is the looming debt crisis as the world wakes up to crazy Keynesianism, as if austerity was ever an option.