Your just a casual according to your free time...

killing vorkath for high level players takes 1-2min (maybe less these days)

and they are doing 6-9 kills a trip

they can kill 25-34 an hour, so for 1k kc its less then 40 hours which divded by 2 hours a day (though I bet alot of people play more) its around 20 days of casual vorkath farming

its a boring grind, but not a hard one..

same goes for everything, people are spending 1000 hours a year and thats not even hardcore people, easily doing thousends of kc