Nah, it's all good
Having companions being playable only add to the game, it doesn't subtract anything at all.
I don't think you are catching what's the issue at hand actually is.
It's not like having a companion playable as an origin story detracts from him.
It detracts from the pool of companions they can realistically implement for a game because making a companion also a "playable origin story" means making that companion several times more expensive to create, both in terms of budget and human resources.
Frankly if put in front of the choice of having, say, 16-20 *good* companions in the game and having 6-8 "playable origin" companions of the same quality I know perfectly well which option I would pick.
I "grasped" it just fine. I just made a choice to make a short comment indicating my thoughts and preferences.
I do not feel 20 companions are better than 8 by default and I feel there are very obvious arguments for why, so I will not insult your intelligence by going through these.
I also feel like cost is a very abstract thing to use as an argument, because cost is not always equal.
Great games have been made with very low cost and bad games have been made with budgets that are almost obscene.
And your argument about having to pick between 20 good companions vs 8 playable companions is not equal in my eyes.
If it is an argument, then I would say I prefer 8 good playable companions over 20 bad companions. Or I prefer 20 playable good companions over 20 good companions.
One doesn't rule out the other.