This is a topic that many people refuse to recognize, but know to be true to a certain extent. Just because the masses flock after something doesn't mean they're doing it solely because everyone else is doing it. Of course half the reason is because everyone else is doing it--most people are spineless sheep with no sense of direction. But the other half is because the game is actually enjoyable.
I spent about two or three months flocking about my cafe, restaurant, amusement park, and apartment on the internet. How did I start? I can't even fucking remember. But I got sucked in. I don't know what it is about these games, but they're doing something right. I stopped after a while, however, because I got bored. But that's just to do with my own preferences.
This same idea could be brought to those seemingly mass-produced Korean MMOs you see popping up everywhere. They rake in people like Lady Gaga rakes in herpes. Because they're doing something right, somewhere. They're free, unless you feel like getting special items, and people find them just as fun as any other MMO you'd spend $15-$20 a month playing. But they play for free. Others might not enjoy the whole cookie-cutter copy MMOs, but there are thousands of others who do.
When a company puts out a product that gathers a crowd, it's good to study the product before judging. It's like saying you hate taking a shit when you've never actually taken a shit before. It feels good.