I don’t think he represented leaded fuel in aviation correctly, although he wasn’t wrong. It’s an economic and legal issue

It’s important to understand this is propeller planes only: jets and turboprops always used jet fuel with no lead. The octane benefits to piston engines really don’t apply to turbines so it was never a concern. However commercial aviation is almost entirely turbines. The most active, profitable and by far the largest part of the industry never had a problem.

Those piston engined propeller planes though… that entire industry was destroyed by litigation and lack of economies of scale in the 1970s. Not only is this a small part of the industry with less profit, not only was the industry mostly destroyed, but now most of those airplanes in active use are old. Very old. They keep flying much longer than for example a car, and there are very few aircraft produced every year. Also note the small volume of fuel used, and lead contamination means this has few refiners and limited distribution: there’s not much profit

So there have been attempts to develop an unleaded fuel for decades, but why does it never happen? Everyone seems to support the idea. Economic and legal. To support a new fuel, engines potentially need to be modified, aircraft performance certified, and someone needs to take legal responsibility for any problems. Who’s that going to be?

• there’s so little (relatively) fuel used that refineries could never become profitable developing a new fuel, could never earn enough to offset liability, could never spend the time and legal effort to get a new fuel approved
• Even if there was an approved fuel, and it was available, and the remaining manufacturers took full legal responsibility, and all new aircraft were certified for that fuel, there are so few aircraft manufactured that it would take centuries to replace the fleet
• Most of the aircraft fleet is orphaned: theirs is no manufacturer. There’s only an owner and a mechanic, and even if there was an approved fuel and it were available, and there were known engine modifications they could make, there’s no way they could re-certify the aircraft with a new fuel nor any way they could cover the legal part
• Most of the fleet has been privately owned for many decades. We have a general legal principal that things are “grandfathered” to when they are first sold. For example, building codes change every year but your house is still ok because it’s grandfathered in since it complied when it was new. Same with most of the small aviation fleet: they’re good when they meet the standards in place when they were new. In most industries, this is not too bad since there’s turnover, but this industry collapsed so completely that there essentially isn’t turnover

So because of the collapsed industry meaning very little new development or manufacturing, the high legal bar because of safety requirements, the sheer age of the fleet, and the general legal principal of grandfathering, there’s just not a way to move forward