I still think that Pace bid against himself, but consider a more obvious overpay:
If the Bears traded the next 20 years of 1st round draft picks and then SF blew every single one of those picks, it was still a bad trade for the Bears unless you think the Bears GM would make the same bad/blown picks. You can only compare the value of the picks at the time the trade was made and what we can determine about what other offers/options were out there, not after-the-fact knowledge. You want to evaluate if Pace made a good or the best decision at the time with the information that was knowable then.
I'm glad Mitch is progressing and hopefully he continues to get better!