Even in Korea, they are way past prime though. I recall up to the early to mid 2000s you could literally find multiple PC Bangs in the same building (on different floors, etc.). Nowadays I'd say you'd be lucky to find one per block/neighborhood, if even that. And those that are still around seem much more sparsely populated.
Not sure if it's too late to reply, but as a person living in Korea now, I can turn around from the cafe I'm in and see multiple PC Bangs.
Visiting one recently, my observation is still quite packed on the weekend, haven't experienced a weekday.
This is in a place outside Seoul and slightly near a popular downtown area. Just felt motivated to provide an opposite perspective based on real experience.
Thanks for the perspective. I wonder if there is an opportunity for these places to service office workers during the day, and gamers on weeknight/weekends? More and more people have the option to work from home, but may want a quiet office nearer their home. They could drop into these cafes for a few hours to get work done. Then come 5pm the place turns into a gaming cafe.