His rinnegan was given to him by hagoromo through sage of six paths chakra but even tho it’s still his eye. The chakra in that eye is not originally his and given how broken his rinnegan is, not being able to deactivate it I think gives some sort of a balance to it
Madara didn't deactivate his Rinnegan rather when he was summoned with reanimation jutsu it would bring the shinobi at their prime Madara obtained Rinnegan when he was an old man
Hagoromo’s Rennigan was permanent also. It was basically his base form eyes just like Hamura’s Byakugan. It consumes no chakra for them while giving them all of the eyes passive abilities. It’s the same for sasuke. It doesn’t consume his chakra when the tomoe aren’t active because it’s his base from eye and cannot be reverted 🤷🏽♂️