lol wow this thread got really upset really fast. The topic about why not making E2 visas pay more... E2 visas are actually not covered under standard Korean labor policy. As in, if you work at a place for longer than 2 years, you become a permanent employee. This is why they keep those salaries low. Otherwise, you'll be a 30+ year old or heaven forbid, a 40+ year old teacher, teaching 10 year old kids. Kids like younger teachers a lot more than older ones and the longer you stay as a teacher, the less "fun" you are. English is unpopular enough as it is, if it is even less fun then good luck making a lot of money as a hagwon owner.
I don't think you'll see anything beyond 2 million a month, at least not until it catches up with minimum wage because they WANT basically 알바생 teachers. It doesn't matter how good of a teacher you "think" you are, the hagwon isn't dedicated to the improvement of English in kids, it's there to make money. You're still making more than public school teachers so both in the private and public sectors will not being paying you much. Plus, there's tons of other administrative stuff going on behind the scenes so the actual budget for a public school teacher for example is around 50 million (Back around 2011 anyway) since it covers your flights, the person working on your behalf for the admin stuff, your housing, and other stuff.
I work in a chaebol now and still, we keep hiring super young and talented translators and designers and never grant them permanent contracts because people just like "Fresh faces." Plus, you have to pay them 8% salary increase every year according to the permanent employment contract so it just saves a crapload of money in the long run, when every new employee just gets whatever their employment agency gives them from our 50 million a year.