...The main reason ... athletes have gotten so much better in the last 20 years.
Also the evolution of defense, as in every sport, and the way the 3 point shot has changed the game, both offensively and defensively in the NBA particularly. How the Bulls would perform would vary depending how much prep time given. If the Warriors stepped out of a time capsule right before tip off - the Bulls wouldn't know what hit them - give them months to prepare - its an exciting series.