Politics -- the bias for the old vs the new. It's taken forever for them to get the lead out of general aviation fuel in the most dangerous, bioavailable and h

Politics -- the bias for the old vs the new. It's taken forever for them to get the lead out of general aviation fuel in the most dangerous, bioavailable and highly dispersed forms there is even though (perhaps because) general aviation is a dying business that could reasonably be taken behind the woodshed and shot (with a lead bullet!) to make way for new industries like drones. On the other hand, new and dynamic industries can bear the burden of switching to more ecological materials.