No one actually thought the Phoenix Suns would trade Devin Booker this summer. They can't exactly enter a full-on rebuild period given their future draft picks are tied up with other teams, but still. Giving Booker a two-year, $145 million maximum extension shouldn't have been part of the plan.
It let NBA fans everywhere know how the Suns feel about Booker, though, and it's that they don't want him going anywhere anytime soon. Put away the trade machine. Booker won't be playing for your favorite team. Even if Phoenix wanted to trade him eventually, a deal would be practically impossible because of his extension.