I believethe flow of chakra is weaking through each generation. Madara and Hashi was born after the Sage's death, not shortly or nearly as long as Naruto's generation. So therefore they have plentiful chakra reserves. I believe when Katsuya ate the fruit and was given vhakra and had a child, it was passed on like a bloodline. Rokudo is the one who shared his knowledge and the way to control chakra, hence the name "god of shinobi". Perhaps chakra was once expandable, and he was able to pass on his chakra to others using a certain jutsu with his rinnegan. This is could be used as a second technique of The Outer Path(Seventh Path). His sons(born with chakra) could not give chakra because they would need both the body and eyes of Rokudo. The first ninja of his age, a.k.a. Rokudo's followers, had the greatest powers would be fact according to my theory.
What if Rokudo sacrificed 9 of his followers, and made them the first 'hosts' of the Juubi. But now their referred to as, tailed beast. Each tail once a follower of Rokudo, the man who gave them the power necessary to control fragments of the Juubi's power. The tailed beasts are very human in some ways, they can talk, all have different personalities, all have names, and they have a father: Rokudo.
Now, generations later very few people have high chakra reserves, or atleast not as high-level as they use to be. And now the Tailed Beasts powers are also weakening, adapting to the change of time. Why would they need to sealed? The empty shell of the Juubi, Gedo Mazo, was placed far from earth when Rokudo created the moon. Maybe the soul of the Juubi remained, calling to his old parts. Maybe because they grow weak, even from the space between them, the call seems to grow stronger, therefore them needing to be sealed.
Because the bloodline of charkra cannot be passed on anymore, Ninja grow weak. The tailed Beast being the last few left with the power of old ninja terms.
What if Rokudo sacrificed 9 of his followers, and made them the first 'hosts' of the Juubi. But now their referred to as, tailed beast. Each tail once a follower of Rokudo, the man who gave them the power necessary to control fragments of the Juubi's power. The tailed beasts are very human in some ways, they can talk, all have different personalities, all have names, and they have a father: Rokudo.
Now, generations later very few people have high chakra reserves, or atleast not as high-level as they use to be. And now the Tailed Beasts powers are also weakening, adapting to the change of time. Why would they need to sealed? The empty shell of the Juubi, Gedo Mazo, was placed far from earth when Rokudo created the moon. Maybe the soul of the Juubi remained, calling to his old parts. Maybe because they grow weak, even from the space between them, the call seems to grow stronger, therefore them needing to be sealed.
Because the bloodline of charkra cannot be passed on anymore, Ninja grow weak. The tailed Beast being the last few left with the power of old ninja terms.
