Let's discuss something more qualitative than quantitative for once, to start the week.
Who are your biggest game changers in K-Pop history? The groups who left the biggest impact. The idol groups who usually come around only once per generation to ignite a cultural reset.
These are the groups where you can clearly and cleanly say they had a transformative impact on the industry.
Here are mine:
Seo Taiji and Boys
SNSD
Six is an arbitrary number obviously, but I think it's fair, since some generations obviously had multiple game changers.