One of the reasons why some people have a lot of gold is many people, like me, don't care for gold so are willing to spend over inflated prices for things.
I normally hover around 20-30k gold just because I like buying vanity pets and I don't see much value in having more than that. Its not like, unlike RL, you need much gold for needs. If you farm your own mats, you need 0 gold basically. If you buy them, its still very, very cheap.