1) boost during covid, post-covid fanbases worked extra hard to keep/improve records from the higher base year during covid. This is particular true for C-bar (usually solo) which aim to outdo each release and compete among themselves
2) better global distribution
3) more fansign,videocall and lucky draw events + photocards. Please look at how much photocards one era could have - NMIXX, IVE, ITZY etc
4) more versions including member cover for regular versions, bringing back the jewel case/digipack which are cheaper +new SMART / QR / WEVerse albums. Those definitely boosted the sales


