So you're asking why there aren't any living shinobi with chakra levels comparable to the Senju or Madara anymore?
The answer is pretty simple. Either people were fearful of their power, and killed those who were descendents of the Senju or the Uchiha, or the maximum chakra capacity has decreased over time.
Those who were not directly related to their ancestors would naturally become weaker and 'diluted' over time.
For example, Tsunade would not have as much chakra reserves as Hashirama's son, simply because Hashirama's son is more closely related to Hashirama himself.
I hope this makes some sort of sense. :ghehe:
EDIT: Seems you changed the question. U_U
