When the Chicago Bulls announced that Cristiano Felício and David Nwaba would start in place of Robin Lopez and Justin Holiday, it was not so that they would win more games. It was exactly the opposite. In the NBA, every bad team tanks. Tanking is losing games intentionally so that you get a higher draft pick. When you get a better draft pick, you get a better player. When you get a better player, you have a better team. When you have a better team, you win a championship. When you win a championship, more fans come. When more fans come, the owner gets more money. Basically, tanking is for billionaire owners to get even richer.
Tanking is supposed to be illegal, but the NBA doesn't enforce the rule. During prohibition, law enforcement knew that speakeasies existed and didn't do anything. When Mavericks owner Mark Cuban said that his team should lose games, Adam Silver, the NBA commissioner, fined him $600,000. That may seem like a lot, but Cuban has a projected net worth of $3.7 billion.
If you want to know why the NBA does not punish teams for breaking the no-tanking rule, you must know why the rule was created. In other leagues, like the NFL, there are powerhouses (like the Eagles) and teams like the Browns (0-16 last season). If the Browns play the Eagles, it will most likely not be competitive. The reason that the NBA established the no-tanking rule is that they hope that more fans come to games, thinking it will be too über-competitive. Again, when more fans come, the owner gets more money.