They still need to be ranked Second Lieutenant in Grand Companies to even purchase a house; which how many level 50 Black Mage RMT do you see in a Grand Company? It's not worth it to them. 90% of the RMT you see in game aren't in a FC much less own one. And as I stated before; RMT won't waste millions of gil on housing when their purpose is to sell gil, not spend it.
