It's super simple tbh. Think about the 'main' roles being supervisors and 'leads' being reg. employees in certain departments. The 'mains' in each category are the ones responsible for doing the brunt of the guides, tweaking choreo, monitoring/participating in production, + https://twitter.com/fentytannies/status/1307723051958706177

and doing the majority of the backup vocals/rapping/etc.

Being a lead doesn't mean they're any less capable or talented than the members in the 'main' roles. It just isn't their responsibility to handle certain tasks within the group.

In the case of BTS specifically, they're all so incredibly talented that any of them are capable of taking over the 'main' role in their respective 'department' if the need arises, but generally speaking they don't have to. It's not their job. +

Their designations only refer to their responsibilities, not necessarily their talent. A 'main' vocalist is not inherently a better singer than a lead. In JK's case, he's main because he's consistent, determined, and has a voice that works well with all of the other members +

of the vocal and rap lines, making it his responsibility to provide support for the other members. He's the one that gets called on when they need backup vocals or a guide.

I've said it multiple times now, but it's just his job. He's incredibly deserving of it, mind you. +

His talent and determination to improve and be involved was likely what netted him that position early on. It also has to do with a willingness to give other members criticism and help them along the way. We see this same behavior come from Jihope when it comes to dancing. +

So yeah. The designations of course have to do IN PART with their abilities, but it more has to do with their responsibilities when it comes to producing/practicing/performing.

Tldr: main/lead titles are just job descriptions. They absolutely ARE signs that the respective members are incredibly talented, professional, and deserving of praise, but NOT having those titles doesn’t mean a member is somehow lesser than those who do talent-wise.

In the case of BTS specifically the roles are more just to keep responsibilities organized IMO. They’re all capable of handling the “main” or “lead” roles in their respective departments and often do trade off roles as they wish.

HEY now that you've read all of that ^ borderline nonsensical bullsh*t, look at this thread I did in an attempt to better explain the roles and responsibilities more accurately: https://twitter.com/_mochikookie/status/1307907209997803520?s=20

side note the supervisor/regular position analogy in the beginning, I realize now, makes no f*cking sense because every job is different when it comes to a supervisor's responsibilities lmao. I was just thinking of my own job at the time. Apologies for that.