A multi-billion dollar entertainment business owned and managed by billionaires who share in the collective success of the league. And there are financial advantages to having specific players end up in specific markets. So there is a motive.
The NBA controls the lottery process. Whether it is envelopes, pingpong balls, or computer-generated number sequences, the lottery process is designed, operated, inspected and audited by the NBA providing the means and opportunity.
Too much money at stake to let chance play a part.