I agree with this whole-heartedly. I remember 3/4ths of the way thru the season, someone posted the preseason Top 15 vs. where teams were at currently. It was laughable. I think there were something like 7 or 8 SEC teams in the Top 15 and when at the time of the post, there was 1 or 2 (Alabama and maybe one other team), vs. 4 B1G teams (MSU, Michigan, OSU and Iowa). I never get worked up about anything related to preseason rankings, schedules, etc because it all works itself out in the end.....just like it always has.
The only argument to really be made on the flipside is that it is much more difficult to move up into the upper echelon of the rankings when you start outside the Top 25 vs. if you start there. However, Iowa made it all the way to #3 from unranked, so it certainly can be done. However, that took a once in a lifetime, undefeated regular season to get there. Teams that start in the Top 10 can often stay there with 1 or even 2 losses, whereas a team like Iowa gets blasted in the rankings the first loss they take typically, unless it happens early in the season (i.e. 2002 loss vs ISU).