Yeah, so what? SM has the highest number of popular acts compared to the other companies, so the math checks out. More acts means more stans. That's really all there is to it.
Notice how SM has a whole ecosystem that links its artists together. They do collabs, special projects, and super groups. They've got subunits within the groups. There's a bit of everything for everyone. It's like Apple, Marvel, and Disney Channel mixed together all at once. When you've got something for everyone, you naturally draw more stans.
It's the philosophy of:
"Different strokes for different folks."
SM:
1. Super Junior (and its subunits and solos)
2. EXO (and its subunits and solos)
4. Red Velvet (and its subunits and solos)
6. SNSD (and its subunits and solos)
7. f(x)
8. NCT (all its subunits)
9. SuperM
10. GOT the beat
11. TAEYEON
YG:
1. BIGBANG
2. BLACKPINK
3. IKON
4. WINNER
5. TREASURE
6. 2NE1
1. BTS
2. TXT
3. ENHYPHEN
and a two girl groups that just recently debuted, so they don't have a solid fanbase
JYP:
1. TWICE
2. STRAY KIDS
3. ITZY
a girl group that just debuted with only two songs