Okay, I'm convinced (at least until I hear equal arguments for the SIR). I've heard enough knowledgeable folks, like George Dean, say that the SIR is a terrible idea. I've been swayed.
I still hope that something is implemented so that you are not forced to choose between steadily losing ground to the latest engine or buying one, along with everything that goes with that (chassis changes, ancilliaries, etc.).
An idea suggested by several is to do something like only allow 2007 & older engines for a few years, or only allow engines at least 2 years old. One great thing about those options are engines will be substantially cheaper.