Perhaps the BEST B1G Forum anywhere, here at College Football Fan Site, CFB51!!!

How different would that 2001 game and season have been for Michigan if Henson never bolted on his senior year? 

I think that hurt Michigan football a lot as well. He was a superstar, #1 overall pick in the making and he just gave it all up because he wanted to be a baseball player more than he had wanted to play football. Kinda the reverse of Kyler Murray. Murray is probably a better MLB prospect than he is an NFL one. He has limited size and arm strength, but he just loved football more than baseball. Henson was a better NFL prospect than he was MLB but he just didn’t love football the way he loved baseball. That guy was amazing in those 9 starts his jr year. He shredded Ohio State in Columbus. Last time Michigan won a game in Columbus actually. 6’4+, 230 pounds and mobile with a gigantic arm. He was basically Andrew Luck before Andrew Luck but with a bigger arm. Same frame, same build, similarly sneakily athletic and fast. Accurate as can be. Gigantic arm. Henson was a freak QB talent. 

This sort of back and forth seems to be common to many rivalries that exist in CFB.  You'd think in general a rivalry would be a roughly 50-50 split, but they seem to run in streaks.  Obviously, some of that is because Team A is better than B for a while, like Clemson and South Carolina, or Alabama and Auburn.

I wonder if each of them has similarly pivotal games where things changed.

Comparing to the WLOCP:
Overall, Georgia leads but it is relatively close at 52-43-2.  Thus, Georgia's overall lead is just nine games out of almost a hundred so an "average" decade would be on the order of 5-5 or 6-4 just slightly favoring the Dawgs.  Of course, that is not how the UF/UGA rivalry has played out.  Instead:
 - Georgia flat out dominated the early days with a 24-5-1 advantage in 30 games from 1904-1951.  
 - Florida then took over and dominated most of the 50's and 60's with a 13-5-1 advantage from 1952-1970.  
 - Gerogia then took over again and dominated most of the 70's and 80's with a 15-4 advantage from 1971-1989.  
 - Florida then took over and dominated the 90's and 2000's with an 18-3 advantage from 1990-2010.  
 - Since then Georgia has a slight 5-3 advantage from 2011-2018.  

ND/USC is another relatively equal rivalry with the Irish owning a 48-37-5 advantage but it has been VERY "streaky":
 - ND won four of the first five (1926-1930)
 - USC won three straight (1931-1933)
 - ND won three of four (the other was a tie) (1934-1937)
 - USC won two straight (1938-39)
 - ND won 10 of 12 (a tie and a loss) (1940-1954)
 - USC won two (1955-6)
 - ND won eight of ten (1957-1966)
 - USC dominated going 12-2-2 (1967-1982)
 - ND dominated going 12-0-1 (1983-1995)
 - USC won three straight (1996-1998)
 - ND won three straight (1999-2001)
 - USC won nine of 10 (2002-2011)
 - ND has won five of the last seven (2012-2018)

OSU and Michigan have large fan bases and have storied histories in CFB.  Some of the other rivalries are more "in state" things, like say Clemson-South Carolina (often not really significant outside the state, and for a long time Auburn was a distant second cousin also).  ND-USC is perhaps close, and I'd say Texas-OU is close. . . .

I'm obviously biased, but I think that OU-Texas is the best since the end of WWII.
Texas leads 62-47-5, with Texas building a large lead with an 8-1-1 start to the series, 1900-1907, and a 15-3-1 run, 1922-1945.  At that point, Texas led 27-11-2.
Since then, OU has gone 36-35-3.
It's been a streaky series.
In addition to the streaks I mentioned above, OU went 9-1 from 1948 through 1957, Texas went 12-1 from 1958 to through 1970, OU went 5-0 from 1971 through 1975, OU went 4-0 from 1985 through 1988, Texas went 4-0 from 1989 through 1992, OU went 5-0 from 2000 through 2004.
Since then, not so streaky.  The longest has been a 3-game streak for OU.

A rivalry can be more relevant for a period of time nationally.  A true rivalry remains intense no matter the significance.

Clemson-South Carolina is pretty intense inside that state.  Texas-Arkansas did indeed used to be significant, 1969 I think it was the game of the century.

Nixon was there, maybe 1970.  I think Arkansas changed conferences or something.

Was it 1970 or 1971 that Nebrask/Oklahoma/Colorado finished 1-2-3 all in the Big 8?

Was it 1970 or 1971 that Nebrask/Oklahoma/Colorado finished 1-2-3 all in the Big 8?

1971 it was.

I'm obviously biased, but I think that OU-Texas is the best since the end of WWII.

Out of curiosity, how do you feel that being in the same conference has changed that rivalry?  

I remember that as a SWC vs B8 game, it was different then.  In a way I think it was more nationally relevant when it was.