Quartz countertops are more expensive than natural granite. They're only cheaper than something like Marble.
Quartz is also strictly a better material: it's not as porous as granite, much much harder than marble (marble can be scratched so easily), and can be made into almost any color or pattern.
Super rich folks may prefer natural stone, but not because it's a better material... it may be preferred because it's a worse material in many cases. The cost and fragility is part of the allure by itself.
