Much has been made about the players who forced rule changes, but I find for at least one of these they are telling us a half-truth that I think should go on the record as corrected.
The league widened the key twice, once in 1951-52 (I think the start of the season) to limit the dominance of George Mikan and then in 1964-65 (start season?) to limit the dominance of Wilt Chamblerlain. The first time it was widened from 6 feet to 12 feet, which causes the markings to lose their key/keyhole like appearance that gave the zone its name. The second time it was widened from 12 feet to 16 feet.
Both of these claims are true. But they leave you with the impression they must have had an effect on the dominance of the players in question, that they ultimately realized their objective.
The 3 second rule was implemented back in 1936 (what purpose did they key serve before then?), but it was only an offensive rule. There was no defensive 3 second violation until 2001-02, although it feels to me like it has been a part of the game forever. So defensive stats which weren't record or weren't recorded separately are irrelevant: the rule change shouldn't have effected how well a player played defensively.
No turnover figures were kept, so it is impossible to tell whether or not he committed more turnovers after the rule change.
But back then, they only recorded total rebounds with no reference to either defensive or offensive rebounds. So some small change in rebounding might possibly be an indication of a change in offensive rebounding. Possibly. Then again, a small change in rebounding might reflect defensive rebounds not offensive rebounds giving a mistaken impression.
For George Mikan, in 1950-51:
Points: 28.4
FG%: 42.8%
Rebounds:14.1
For 1951-52, the year of the rule change:
Points: 23.8
FG%: 38.5%
Rebounds: 13.5
And for 1952-53:
Points: 20.6
FG%: 39.9%
Rebounds: 14.4
It looks like the rule change definitely effected his FG%, as he never got above 40% again. As it effected his FG%, it probably effected his points per game contributions, but changes may be misleading as his scoring appeared to be in decline. Rebounds dived a little at first, then rebounded to a higher rate than even before the rule change even though he saw slightly fewer minutes per game (40.2 for 37.9 and 32.8 for his next season in which he averaged 14.3 RPG).
So maybe it had a small effect on his dominance, but I think the numbers may be a little misleading.
For Wilt Chamberlain, however, it is a different story.
In 1963-64, he had:
Points: 36.9
FG%: 52.4%
Rebounds: 22.3
In 1964-65, the year of the rule change he had:
Points: 34.7
FG%: 51.0%
Rebounds: 22.9
Clearly, not much of a change. A slightly smaller FG%, but less than the difference seen in Mikan. Both his points per game and FG% figures may be misleading, however, because he played half a season for the San Francisco and then Philadelphia: the same team relocated, but showing his points per game where higher than the previous season at San Francisco and his shooting percentages were higher in Philadelphia. In the season after, his FG% was back up 54%. His FT% also took a more significant dive than his FG shooting that season before rebounding the season after and clearly that has nothing to do with the widening of the key. So to me it looks like the small loss in shooting was just natural variation. I don't think the rule change effected Wilt Chamberlain one bit. Which might explain why the NCAA didn't follow suit in widening the key further.
So the rules may have been changed to limit those players dominance, but it seems to have had no actual effect in Wilt's case. You might view this in one of two ways:
1) The rule change was simply ineffective.
2) Wilt found a way to improve himself as he always done and overcome whatever obstacle was thrown at him.
Either way, the widening of the key from 12 feet to 16 feet seemed to have no effect using Wilt as an example.