So if I made a 100mpg vehicle but it only runs on leaded gas I guess you have no problem with it being on the market. After all, "damn that thing saves a tonne of fuel and is probably doing more to save the environment". It may be saving the environment on gas consumption but is polluting it right back with lead.
From my understanding it wasn't a matter of a product "that just barely can't meet ridiculous emission laws". During normal driving the NOX emissions were as high as 35 times the accepted level.