Start of season's always hot. This year's especially big game hot, considering it's Oklahoma. Feels a bit like the 2000 Florida game, which was (inflation adjusted) the last time I remember an early season game riding so high up the charts. The sellers want people with more money than sense right now, and if some knucklehead's willing to give them 400 a ticket they're going to take it. Websites in this setting are not a good predictor of gameday prices, just a predictor of how much sellers think they can get from the people who buy in early. Just take it under advisement.
There'll still be people selling on gameday, and there'll still be deals. You just have to knuckle down and be willing to gamble and lose -- and if you can't get a reasonable price, as you said, go watch it on the TV. This is one of those "maybe get a ticket a few minutes after kickoff" games. Which. You know what? It's been a long time since we've had one of those, for real, for big game marbles. Should be fun!