Bottom line is that general aviation regulations are to a large extent driven by the public’s illogical perception of GA as dangerous and as a consequence there can be illogical requirements set by their bureaucracies.
Atrial fibrillation requires a special issuance for 3rd class but isn’t a factor for BasicMed so that leaves little option for us elders.
I suspect that ICAO over regulation is a significant driver of 3rd Class Medical requirement while US pragmatism is the determinant for BasicMed.
As was pointed out a GA pilot self regulates every time they leave the ground.
So the US, Mexico and to some extent NZ think BasicMed is fine but Canada and the rest of the world don’t. Can’t have much respect for strict rules with that kind of uncertainty.
Interesting to see that total number of “medicals” is constant with 3rd Class decreasing and BasicMed increasing by the same amount.