From where I sit it looks like the NBA doesn't have any ability to prevent teams from playing poorly...
The idea of tanking at the end, or even midway though a poor season is nothing new in sports. Ask the Ottawa Senators about that. The current plight of the 76ers is pathetic. Their streak of losses has been well documented and ranks among the sports worst. It's awful to watch and miserable for fans. It shouldn't happen to any team, particularly at the professional level. That being said, how would the NBA force them to win? Put a cap on the number of minutes starters can play? Give Philly 6 free throws to begin every quarter? Let them play the Washington Generals? Sure, it's painful but the Nets were a woeful 12-70 four years ago and are now the second best team in their division. It should also be noted that Milwaukee is worse. The Bucks are a brutal 13-58, but have managed to space their wins out a bit more evenly. In sports of all varieties in order to have winners there must also be losers. Just as there will always be great teams with impressive records, there must also be terrible teams dwelling at the bottom, dreaming of better days to come, or revelling in past glories. However, every team, no matter their record, enters every game with one purpose. Win.
At least that's how I see it...and I sit in the cheap seats.