Earlier quoted context omitted.
Don't rule out another Cash for Clunkers. The 2009 program destroyed 1 in 300 cars on the road. The next one could be bigger. Also, 3 in 4 cars on the road today are now in states requiring emissions tests for your annual registration, which can pose a significant (and growing, as standards improve) obstacle for older cars.
The article is about the EU, but since you brought up US emissions testing... I live in California, only drive mid 2000s cars, and haven't noticed any of the restrictions getting tighter. It's the usual check every 2 years at the same place. Seems my cars are grandfathered into old emissions standards too. And yeah I enjoy having my car shut the hell up and let me drive.
Last year, or the year before, Texas dropped emissions testing, except in its most populous counties.