Some people get a good system going and scale up, its just very volatile for most people without a huge risky investment. You also get varying costs and gains. 2k p/h is not always a lot, there are often mini gold mines especially during expansion launches or major patches where BoEs and future unobtainables can be of ridiculous value, some people even exploit then mule those gains (not getting into that), different people do different things with a different set of internal rules. The thing preventing me from botting gold full time is mostly I have nowhere to get rid of it. I tried once and found a guy buying it almost like an addict, but he left the game, and I've been ripped off twice too. I imagine with a lot more experience and product these issues might resolve themselves, but I'm a good coder, so I just do other things. I'm still interested though, maybe sometime ill code an automatic character mule creation and gold mailer, then tie that to an online store which can ban people who chargeback, and require payment first etc, but even then, you'd have to drive people to it without spamming the game and getting sued (in a western country + I actually like the game, so f that) .
Most of it is quite easy for me really, I could monitor gold on each realm and mule it and automate everything, but where the heck are the buyers? If there was a central market with reliable buying power for games, I'd bot everything and keep my stock auto-updated.
Edit: btw even after nerfs if you have the toons for it, the cata raids are still easily 5k per toon. I run them manually just for game tokens, but there are scripts on the store I've seen, and maybe others.
Second edit: Do not link anything here publicly as I did check it it will be against the rules and considered advertisement.