That's wild to me too, but rich lazy people who subcontract out everything is much better for society than rich people who hoard their money forever, so I'm certainly not going to shame them about it :)
There's as much here that's cultural as economic. There's no ceiling on how much I'd have to earn before I'd pay somebody to do that kind of work for me, because (for someone with my working-class background, at least) hiring someone to do that for you feels degrading and emasculating.
It's a simple task you can and should do yourself. Money has very little to do with it.
It doesn't really matter to me why they're rich as long as a proportional amount of their earnings is reinvested in their local community, jobs, and infrastructure :)