Actually, he is a max player in that he's making the maximum allowed under the current CBA. He signed a max extension back in 2013:
DeMarcus Cousins signs extension
"The Kings signed Cousins to a four-year
maximum contract extension on Monday, saying the 23-year-old center is the foundation the franchise will build on to lead a struggling team into a new era."
There are other players making more, but he's making the maximum allowed based on his circumstances. He has two more seasons left on that extension and I'm sure someone will throw a max contract at him when he becomes a free agent that will make him one of the highest players in the league.
BNM