Why is bts the only hybe group with official positions??

They're so strict about it that even when casually standing they follow their positions but other groups change potions in mvs and performances.

Good question

BTS was the first Hybe group after all. They debuted when idol groups usually have clear positions for each member. time changes and now it doesn't matter much anymore.

We all know why

because in bts, members in respective positions actually really excel in those fields unlike other hybe groups where members are more like all rounders

E.g. no hate to text but they don't have even one member which have rap skills like bts rap line, in dance, they are all more or less equally excellent. So you cant assign specific positions to such groups and there is also no need for it.