Display MoreYes, but the more interesting question is how they get those sales without gp interest, and why gg generally are not able to do the same thing.
AKB48 is an example of a girl group that could sell way more than their popularity with gp would suggest. They did this by appealing to "whales": single (in both senses of the word) men who would buy very large numbers of albums. AKB incentivized this by including tickets in the albums that could be used to vote for their favorite idol and to get into handshake events (i.e. meet their bias in person).
I think something similar is happening with kpop bg, but not to the same extent. I think in this case, they are simply able to motivate their (95% female) fans to actually buy the album (usually one) instead of just streaming. Fans do this to "support" their bias(es), similar to the motivation in the case of AKB, but there are more fans with less disposable income (because they are usually younger and from less wealthy countries than Japan).
Why kpop can't do the same for gg, I don't know. AKB proved it's possible. Maybe less male fans are willing to "support" idols by buying albums, and the possibility of contact with the idol is a necessary ingredient for some male fans to become whales to make up for that? ...and kpop just doesn't want to go there (especially now)?
Correct me if I'm wrong, but K-pop GGs also do fan meetings and stuff where they get to meet their fans, just like BGs. Even now, in the pandemic, there were virtual fan meetings happening for both BGs and GGs.