Firstly, while not many guilds can take it down, there are still some, and don't you think that if a guild can do this, they've probably done many MANY runs to get the Zulian Tiger? and Secondly, I recently rerolled on a new server, I'm not even 70 yet and I have my 1000g for my flying mount, including TWO Primal Mooncloth bags so far, they're ~400-450g on my server (Frostmourne). I'm a BM spec hunter with Mining and Skinning, so easy to get gold it isn't funny.
Don't just assume that because someone has insane gear and gold they're on a private server. People like you make me sick "waaah waaah he has uber gear, must be a pserver or ebay!".
Though granted it is possible, just don't assume it. It makes you look like a child.