To be blunt, the Mavs are due to suck.
It happens to everyone — literally everyone. Since 2000, every single team in the NBA has bottomed out for a period of time except for the Spurs and the Mavericks.
Seriously, every other team.
Powerful, historic franchises like the Lakers, Celtics and Knicks? They’ve had some years of suck since then. The current cream of the crop of the NBA, the Warriors and Cavaliers? They’ve totally sucked, like big time. Hell, the Warriors went from arguably the worst franchise in the NBA to the gold standard over the course of Dirk Nowitzki’s career.