Board Thread:Naruto Discussions/@comment-27521865-20190624190722/@comment-27973430-20190625194306

@Missy0124 Kekkei tota is a big unknown no one knows how it works and nowhere has it been stated that kekkei totas are just more powerful kekkei genkais.

Yes, Obito under the alias of Madara said that he implanted the eyes into Nagato because that was what the real Madara did. You can find references for it on Madara's and Nagato's pages.

I don't think Itachi's whole story makes much sense either, but that is the reason and the answer to your question even if you like it or not.

Not true. Hiden has been stated to be unable to "be copied through simple observation" (to quote from its page) and most are not kekkei genkais.

The world doesn't revolve around the Otsutsuki, Uchiha, or Senju the only thing that did was the story that was told and even then only in the latter parts of the series was the story revolving around those three clans. A great story can be told about any of the weaker ninja clans or anybody who isn't part of a ninja clan, it is just not the story that is getting told.