Parcells, Walsh, Noll, Landry, Reid, Holmgren, Kiffin, Jim Johnson (Eagles DC). Those guys all did pretty well with a system that they put players into, as opposed to the other way around. I mean, every coach has a system. Yeah, some are more adaptable than others, and some (like Harbaugh and Shanahan), had success adapting their system to fit their QB, but most of the successful coaches are the ones who can get the right players to fit their system.
Honestly, I could really care less what Simmons thinks.
There's always more to the story.