he problem is that the "U.S" – i.e., the federal regulatory apparat – never imposed Automatic Stop/Start (aka ASS) on the vehicle manufacturers. It is strange to speak of "axing" that which was not imposed in the first place.

More like inaccurate.

ASS was imposed on us – by the vehicle manufacturers – as a compliance measure. The system does that by eliminating – temporarily – any "emissions" of the bogeyman gas that has nothing to do with pollution (i.e., CO2) and very slightly upping fuel economy – by automatically shutting off the engine whenever the vehicle stops briefly, as at a red light. It also does the same when you stop to park, which is annoying because people often don't realize the engine is already off and reflexively push the stop/start button to shut the engine off and that causes it to start when they wanted it to stop.