Brave Entertainment just drops the ball on promoting them and always has.
Like, they came out of the gate strong in 2011, then radio silence for YEARS until they pushed out release after release in 2016. And then jack all until Rollin' randomly went viral and they tried to capitalize on that, and dropped the ball again.
Their music has never been the problem. Thank You was such a good mini that got better with every listen. Like BG's popularity is one where you can solidly point to the failures of their company to promote and manage them properly, rather than lack of talent or bad songs.
Why yes, I am perpetually bitter that they wasted Hyeran's talent for years.

And even lucking into success, their company still can't get its shit together.