He is the most popular member in the west. Plus he got that quarterback image. The 'I'm good at the things I want to do' stuff. It's a very hot public image and it will gather attention.
He can sing, dance,rap, and he also produces and write songs too. Plus he is hot so he got every single thing covered for solo. He also have very loyal fans.
But I feel like since he started BTS at a very hard age, he might be dependent on the members and might find it hard to go solo since BTS practically raised him. If the time comes for BTS to disband, I'd want to see him go solo tho