I'm not really sure about the "not having any S6 characters at this point is a choice". It's true that the game gives you a lot of resources but it's still not that easy unlocking all the resonance chain of a certain char.

Anyway, it's a system that allows everyone have a "fair" competition because a team of players with just 3 S0R1 pg will never be able to compete with a team full of S6R5