They work within a niche space, as others have said, they follow where the work is, So they are able to charge more which I hope is able for them to survive in modern economy and be able to give more time to their family.

atleast that's my interpretation of it of how logic might follow if they are working in niche space, many people seem to be applying the logic onto themselves into completely standard situation, but I don't suppose that is the case here.

Hope this helps in genuinely understanding their situation, from my reading/thinking about it.