Maybe yall weren't around or are looking at 2nd gen with 4th gen glasses.
From 2011 to 2015 f(x) was always a top 5 girl group.
They were pretty much #3 in music video views and album sales behind only SNSD and 2NE1.
They also won more critical acclaim than any girl group in history of kpop. Someone posted a chart with this proof months ago (please post it again in this thread for proof).
f(x) was also one of the first popular groups in the west. They were first kpop group invited to SXSW Music festival and even went Hollywood in 2012 with Anna Kendrick Electric Shock crossover.
I've seen just as many people comment on YouTube that Hot Summer was their introduction to kpop as I've seen people comment the same on any other kpop song.
f(x) was big time. Please learn your history so you don't look noobish to other kpop fans.