I guess it depends on what criteria you think "Power Rankings" or preseason polls are judged on.
You could say they should be a reflection of a team's final ranking from the season before. In that case, Nebraska would be in the neighborhood of 25/23 (AP/Coaches).
Or you could say that they should be in anticipation of where the team might end up this next season. Nebraska has finished the last four seasons ranked 25/23, 24/24, 20/19, and 14/14, so that's probably a pretty good predictor of what we'll do this year too.
Or you could say that Vegas does a better job at predicting things than anyone else (which is completely true), and then note that we have the 19th best odds at winning the national championship. We are also not even favored to win the Legends (and tied with Michigan for 2nd place), and tied with Wisconsin for 4th place in the conference.
So, actually, it doesn't really matter what criteria you want to judge a preseason poll on and the conclusion remains the same: he's more or less right.
While I'm not sure if we deserve to be completely unranked in his poll, I wouldn't say we really deserve to be much higher than 20th either. I also don't think there's really too much of a difference between being anywhere around the 20's, so I don't see the big deal. Our preseason ranking in each of the last four seasons was 17/16, 10/11, 8/9, and 24/22, so we've been moderately overrated each of the last three seasons. Maybe they're just reacting to the fact that we've underperformed relative to expectations lately.