Yes, all the companions we meet should be level 10. But does the game need it? Is there a point in screwing the game mechanics derived from D&D just to satisfy the thrive for authenticity and logic of some players?
Again, it's all about consistency.
Maybe you don't really care... And I have to admit that in a game like DoS it's not a problem to me... But BG3 is not sell as a DoS game.
I guess when you write stories from nothing, you can easily choose to be consistent to the rules/the lore of the world in which your stories take place... Or you can choose something else. Whatever your choices, your stories can be interresting and engaging.
