Display Morehttps://www.allkpop.com/articl…-in-album-sales-this-year
This is them in their debut era. I know you know how crazy this number back in 2nd gen. Yes they're in decline now and their popularity is not like back then when they're almost on par with big 3 groups and have amazing digital sales, but they were never in nugu position. Bts only sell 34 copies of albums on their debut day. They're one of the best story of rags to riches in kpop so, idk why they're not suitable as a judges just because they're too successful. Didn't this what those groups needed?
But ngl, when I make this thread, Gi Kwang and Sung Kyu are definitely not the one who I think can be replaced.
I get what you meant in your OP now.
Personally I don't think BTS would necessary be suitable judges because their circumstances were too unique (like the rise of social media, now most idols heavily use social media to connect with their fans) and would be difficult to reproduce in current kpop. And for the famous part, well usually it's more difficult to empathize with people who are in a situation far removed to your current own as humans in general. But it's not like I know them personally so who knows they might have killed it.