To what extent is modeling a success indicator for idols compared to music? 43
The result is only visible to the participants.
IMO, modeling is the biggest indicator of an idol's demand and it starts with their merch and photo cards selling out and then the albums with the most individual details that in turn increase the number of preorders and album sales in general.
Seeing how much individual former Exo members make in China explains this so well. They each make as much as most if not all top-tier groups make in Korea in a year.