Insurance companies are very, very good at figuring out how to identify and price risk, once motivated to do so.
Also from what I've seen there are way too many GA accidents involving airline pilots for the insurers to eat that loss. They almost invariably have superior skills, but some of them more than compensate with risk taking.
But if they noticed that they were paying out more than expected on these $500k deals, the insurance would change quite quickly.
The same thing happened with GA insurance - there was an assumption that airline pilots would be safer but it didn't really turn out as expected, because a 747 has a heck of a lot more "keep you safe" doohickeys and doesn't fly low to the ground much.