If you concede that a search incident to arrest requires no warrant, you've already conceded the argument that the Constitution doesn't require warrants for all searches (which is good, because it clearly doesn't), and we can move on.

Regarding your second point: the change was not "states" vs. "people and the states". The change was whether the rights referred to were solely those expressed in the Constitution, or something broader. Broader won. This is an argument you are going to need to take up with the authors of the Constitution, because they do not agree with you.