Does going from scoring the top six to scoring the top eight meet your standard of a SUBSTANTIAL rule change? They started scoring the top eight in 1979. Did the change lessen Gable's team in 1981 record breaking tally of 129.75 over Kurdelmeier's team in 1976 123.5?
How many eras do you propose to parse out?
I ran numbers back to 2010 and these are the point totals for the top five starting at 2010: 439, 423, 539, 491.5, 450.5, 406.5, 466.5, 543, and from 2018 to now I already laid them out. It seems that strong teams at the top lead to top heavy point totals because the highest totals going back to 2010 were 543 in 2017, in 533 in 2018, 491.5 in 2013, and 484 in 2021. So even with the new rules the top five only accrued 451.5.
It appears the 2-5 teams really didn't benefit from the scoring changes. First because PSU is so dominant that they didn't allow much team scoring. I believe they lost only 9 matches. 2 in the finals, 2 by Davis, one by Kasak, 2 by Nagao, and two by Truax. Their record was 45-9 so they weren't allowing much in the way of team points for their opponents.
No one sets a scoring record without being a great team, a majority of all Americans, wins in the finals, and bonus points. In 2018 PSU went 4-1 in the finals, Hall winning would have put them close to 150, with OSU still in the mid to high 120s. So again, the final thing you'll need is to be head and shoulders above the rest of the pack.
That is why baseball discusses asterisks for certain records. If you have more games to hit more home runs, of course the record isn't the same. If you only have to get 2 takedowns an escape and riding time to get a MD, that is absolutely different than needing 3 takedowns an escape and riding time when that is essentially impossible to happen without giving the opponent an escape point...
With that said, PSU was so good this year, they deserve all the credit in the world for breaking the record. But, that doesn't mean the rule changes didn't help them do it...
Baseball is the absolute worst example to use since they excluded an entire race until 1946 and didn't fully integrate until the early 60s or so. Then we had them overlook steroids for a decade ( they knew what was going on) until it couldn't be ignored.