That's true, but the actual and more dominant reason in not having potent enough chakra. Because if it was quantity, they would still be able to manifest it for a considerably lesser amount of time.Susanoo's progression is reliant on the potency of the chakra, yes, but to manifest a larger Susanoo you would clearly need more chakra, and going off of the feats from MS Sasuke and MS Itachi, they don't have the chakra to manifest a Perfect Susanoo despite having the the eye needed to do it.
You could have stated it in a better way. It was ambiguous.:lol Don't take one part of the sentence and reply to it. The whole sentence means that you can get PS regardless of having EMS or MS, meaning you only need either or. Not neither.
You can do it, but you can only maintain it for a much lesser extent.Wrong. If you don't have the chakra to manifest a Susanoo, then you won't be able to do it.