“The good old days........”.
Many of the rules are to prevent escalations that lead to brawls. Rudy Thomjanovich getting his face broken and the Ron Artest fight where fans inflamed an already intense situation going on the court spilled into the stands. This was part of it. Baskebball is played professionally with no barriers between fans and players. They had to stop the fighting and the physical play that leads up to it.
Reduce injuries? I wish we could see if your theory has statistics to back it up. Player contracts have risen and protections are on the few mega contract players that hold those big money deals are a problem if players get hurt. I agree few injuries a via contact.

Ratings in the 90’s era of hand checking and lower scores did matter. The product has to be attractive. Hand checking was a variable that allowed star players to get calls at games end. Jordan got gifts all the time to finish. YOu touched him it was called. I recall the infractions were inconsistent to how they were called and we had perhaps even more “Conspiracy” about the league and its desire to promote one over another. Perhaps the more athletic the game got the more danger for players to get hurt via hard fouls. Stars were thought to needing protections. Players union did not protest the protections did they?
While Knicks and its fans liked the low scoring intense defensive battles it failed to attract a growing audience. Money matters in pro sports. Football has been nurtured in many ways also. Hockey had also also lower the violence factor as some horrific visions were appearing.
Pro boxing is hardly a big sport anymore. if you watch an old Rocky movie you can see how cartoon that boxing scenes were were obviously orchestrated and extreme are nearly repulsive now in its brutality. Bloodthirsty fans are fewer these days. simulated violence in WWE became far more popular as has the mixed kick boxing which has its following but not like the days when the heavy weights ruled pro boxing.
Idiot obstacle course game shows with participants getting beaten up by stupid moving objects are all the rage instead. These are the new Gladiators of the times?
Baseball is more guarded in activities that prevent injuries and fights, Football has rules about hitting, Hockey does not promote fighting and has its rules, so has basketball. Seems real violence involving guns is more real than ever.
I’m not defending the rules but perhaps just discussions why they exist helps to understand.