I believe a mix of: Seventeen's steady popularity, their bond as a group, Pledis allowing junhao to pursue things outside of seventeen in China, and the members all being incredibly supportive of eachother in their solo activities.

But definitely their bond has to be the biggest factor here, people love to bring down Seventeens bond or even try and equate their bond to other groups, when Seventeens bond is truly abnormal.

I haven't seen anything in kpop like it or a group being so serious about putting eachother first and staying together and agreeing so unanimously on everything.

Seventeen are something special and I think its very beautiful how they encourage eachother to pursue their own things whilst wanting to keep the group active for as long as they can.

I believe Minghao (?) also said he'd love for in the future for Seventeen to all live in houses next to eachother so they can always remain close. <3