Pre 9/11, obtaining a Temp US Airmans Cert was a simple matter of calling up an FSDO and arranging to visit them (20 mins was all it took, and I was on my merry way) and the cert was free.
I would imagine that the FAA looked at a whole array of options available to them post 9/11 - it may well be that one option they might have considered was to stop the issuance of such licences. Personally, I've never heard about them being curtailed but perhaps someone with more up to date info than I may be able to shine a light on this.
PD,