Yes, TX-USC was a perfect storm. I witnessed that first hand. Of course most Texas fans that lived that experience then overpaid for TX/Bama a few years later (you could get tix day of cheap for that one). TX-UM would have been the same 2 years ago and probably worse than TX/USC (inflation adjusted). Yes, I recall ND/OSU was pretty high last year as well. I think PSU and ND would drive prices up the most from list posted above this year if our opponent. OSU would be a last years semi rematch, opener rematch + OSU just won it last year so I don't think that pricing would be as high for that matchup as it would be in normal years.
To keep on topic, I think buying it at $700 for an option you would be able to flip that seat early championship for a pretty nice profit regardless of opponent for sure. I just think that is a super high price to pay for an "option" preseason that probably has around or less than 25% chance at hitting.