There is a tremendous amount of evidence to support this, free rushers aren't always the OLs fault and it's been a common occurrence for years. I will say, rarely does it seem to have a negative impact until this season.
There is a story where Favre went most his career without knowing what a nickel defense was, and was too embarrassed to ask. When he finally did, and the answer was provided, he responded "oh... who gives a *****?"
Farve is a legend, but what could he have accomplished if he actually worked on his weaknesses and not tried to out gunslinger everything?
I think we all want to see free rushers handled better than "who gives a *****" pre and post snap, especially as he is getting older.