Most [piston] engines? Yes. Most gallons of avgas bought per year? No (or at least until G100UL has an all-model certification to replace 100LL). I posted more details in a sibling comment here.
(I want nothing more than to be able to buy G100UL.)
Notice "not poisoning children" is not on their list of requirements. No, just that it doesn't cost you any money.
If I just took TEL and sprayed it over your house, I'd be arrested and have to pay tens of thousands for remediation. But do it in a plane? No problem!
(I want nothing more than to be able to buy G100UL.)