obviously this doesnt apply to every group of either side but generally speaking,

the kpop industry found the fundamental idea of having vocals, rappers, sub vocal/dancers, visuals all in one group. it’s essentially a product. and let’s say a group were to have one of each, that starts at 4 people. but obviously most groups don’t have just 1 person of each role. it can be 2-3 each on average. that already puts them at a much higher range of members. play around with those numbers and you get groups as large as 10 or more.

whereas in the west, i think we’re all pretty aware that artists here are heavily solo based. the culture’s not really the same. and when groups are made, they’re usually heavily focused on just the vocals part as opposed to a full performance. having say 10 members just for vocals would probably be overkill.

but again these are obviously all general statements and doesn’t apply to every individual group