Just be cause the defense in the NBA doesn't look like it used to be doesn't mean it's not what it used to be. The game has completely changed. And it's more than just making more threes. The fact that offense has improved doesn't mean defense is bad, it means offense is just much more advanced and harder to stop.
Everyone in this thread saying modern NBA doesn't play defense just reeks of old heads complaining about how times have changed. The defense is ten times more advanced than it used to be, the problem is the offensive game has advanced even further.