I agree that it is now much tougher to get to the title game, there is no doubt about that. This is true of every team in every conference. Not sure what the point is of digging NU out separately?
Thinking we only had to play Oklahoma to get to a title game is simply inaccurate. I am not sure if that is due to ignorance or intentional. NU did it on the backs of playing multiple top 5, top 10, top 20 schools in most of their runs. In the 90s alone, they averaged 4-5 top 20 teams per year and most of those years half of those were top 5 teams.
At any rate, I am not sure the fascination of the 80s as NU won nothing in that decade although they played for a couple of titles early on. As I've offered elsewhere though, the proof is always in the pudding. In the T.O. years, the big 8 won 9 national titles by 3 different teams and the B1G won 1. NU alone went 22-2 against B1G teams.
One of those 2 losses should thrill you though, it kicked off the Hayden Fry era and was the first win by Iowa against in a top 10 team in like 100 years. Heck, you went on to beat 3 of them that year. See? I can do hyperbole too!