U need hamura's chakra to awaken tenseigan. Toneri said he was the last otsotsuki,and hamura was the creater of shinobis on the moon. So he was related to hamura,all he needed was a byakugan user,(like hamura's eyes) to awaken tenseigan.
Rinnegan is senju+uchiha,but tenseigan is hamura's chakra+byakugan.
Sasuke and madara don't have hamura's chakra,and they aren't otsotsukis. They are uchihas who mixed their chakra with senju(in sasuke's case he got it from Hago himself) and GAINED hago's chakra.