How did fights go from 15 rounds to 12 rounds?

That's exactly what happened as stated above.

A US school located in a certain state used to serve peanut butter sandwiches until one kid died from having an allergic reaction to peanut butter. Now no schools in that state are able to serve peanut butter & jelly sandwiches. :bart

 

The official reason was fighter safety. Mancini-Kim went 14.

Others believe it was to fit 12 rounds + intros and interviews into an hour time slot. Boxing was pretty big on network TV then.

Mancini-Kim is also credited as being the fight that led to day before weigh-ins, while others believe it was the aborted Michael Spinks-Eddie M. Muhammad rematch. Maybe both.

 

Study your boxing history folks, it was the death off duk koo kim & tv pressure that caused the demise off 15 round title fights!!!

 

11 or 13 round championship fights would make less draws, giving fighters chance to break a ties. As for shady judging make the judges take a lie detector test. Sure they can be fooled, but at least its a step in the right direction.