Sounds about right, I don't know how anyone could look at their players in the NFL and say the school's players haven't been successful there. Maybe it's because they are mostly defensive players who don't get as much of the spotlight as the offensive darlings the media prefer.
In any case, blaming a college coach for NFL players perceived lack of success is completely stupid. Mack Brown isn't paid to win games in the NFL, he's paid to win college games. Whatever style happens to do that best, they will employ, regardless of whether or not it prepares them for the NFL. If the kids have talent, a good work ethic and determination, they will likely be successful at the next level.