The 30 years thing is insane for sure. Making more money than the average might be insane, it depends on how much more (which I didn't spot in the article, maybe I missed it).

the other issue is, there are lots of people who work and help out in the countryside where cost of living (and hence wages) are very low and forcing them to be above the whole average of the county is a bit onerous i think.

probably a better idea is average for the prefecture they live in, but i guess they want to simplify things or discourage ppl from moving to the countryside? idk; most people are in tokyo/osaka to be sure...