Wrong on all accounts. There are orders of magnitude less engine models used in air than cars. Profit margin for airplane companies are higher than cars (though volume is much lower). cars use the same model worldwide and pass certification all at once, planes sell in one country and customers are mostly responsible for 'acclimatization' or whatever they call it in your parts, but it usually is about lights color and placements or some nonsense.

the one thing that made planes be so slow, is that people who own planes have much more voice over legislation than people who own cars. Nothing else. That's why the whole industry used tax payer money to certify one special new gas type that will work on all existing engines (again, possible because much less variety, making it easier technically). You breathed lead for 60 years of legal lethargy just so a few people didn't have to spend a few pennies on their plane maintenance.

I thanks the FAA and other's countries flight authorities for the fact that I don't need to have an anxiety crisis every time a plane passes overhead.

Oh, and unlike with a car or truck, engine failure in a light plane, especially during takeoff, is VERY likely to result in death or serious injury.

Well, what are the safety implications of atomizing lead? This argument seems short-sighted.

There was a carve out because plane engines are expensive and old (the most common engine today is a 50 year old model). Presumably it was expected that carve out would just be temporary while we worked on finding an off ramp to unleaded avgas. Nobody wanted the FAA to just ignore the problem for decades.

It's notable, and is being banned for it. But when it's gone, it won't make any significant difference.