Where exactly did you get the conclusion that environmental progress is stopping?
It's possible in the US that emissions and fuel economy standards are going to be stopped or be rolled back, but outside of the US, standards are still advancing quite rapidly - possibly more rapidly in Europe, due to standards changing in response to widespread cheating.
All that means is, the new engines are going to have larger displacement, and less turbocharging.
Originally Posted by Lug_Nut
The really cool ToofTek made "Emperor's Clothes" injector fork risers only worked until someone pointed out that there wasn't any thing there.