I wonder how much of it is being driven by paper v/s polymer lobby. From what I read it appears that polymer (read securency) substrate has had a long monopolistic run. Being partly owned by the Australian Government certainly helps the cause.
Only recently are there viable competing technologies for alternative substrates in polymer.
There was a nice article in the CPMS journal that was based on discussion with an Australian (it being the first country to have a widespread launch of polymers) note dealer Trevor Wilkin (web site:
http://www.polymernotes.com/intro.html)
Essentially Mr. Wilkin seemed to suggest that for the polymers to be collectible they would have to be taken off the production line because otherwise they tend to crease and fold real fast.
The claims in regard to life of polymer being long refer not to its propensity to crease and fold faster than paper but to the more damaging aspect to longevity of notes soiling, tearing and other deterioration. In this regard polymer notes come out much ahead of paper (technically cotton).
The article in the CPMS journal is worth reading.