A historical perspective:
The original addition of TERPs became effective in November, 1967. I don't recall how many revisions it had.
The second edition came out sometime in 1977 and we know it had many revision, up until last year.
Also, now we not only have the third edition, we have adjunct criteria in the RNAV Order 8260.58A. For a few years we had the RNP AR standalone Order 8260.52, which was subsequently rolled into 8260.58.
Garmin is pushing for RF legs to LPV, which presently exists in Switzerland. (LSMD)