There's a significant down-side to isolation ball. Teams that become too reliant on a single player can become stagnant on offense, too one-dimensional, too vulnerable to teams that have that one lock-down defender that can take away the isolation play.
Some of the NBA's top scorers - Kobe Bryant and Carmelo Anthony, for example - thrive in isolation. They also draw a ton of criticism for taking too many shots, being "ball stoppers" and not involving teammates in the offense enough. And certain NBA coaches are notorious for allowing their offenses to become overly reliant on the isolation play. When he was coaching the Cleveland Cavaliers, Mike Brown's critics described his offense as "give the ball to LeBron," while Mike Woodson's system in Atlanta was mockingly called "iso-Joe" due to its utter reliance on Joe Johnson. Today, Brown coaches Bryant with the Los Angeles Lakers and Woodson heads Anthony's New York Knicks.