how come kill this love still sell so much even after 2 years ?

i am not into kpop when kill this love released but i seen some old threads there is so much negativity in this era people called this was their flop era but even after 2 years kill this love sell more than 11000 album sales which is more than the album and its soon going to join 500k club it is really great how people called their flop era turned into one of best selling album in their carrer