Best color commentator of all time? I'm not sure. That's quite a claim. He's good at it.
I think it comes down to his desire to coach or not. Coaching, quite honestly, seems like a sucky job. Very, very long hours. High stress. Low job security. Moving your family around a lot.
Yeah, you can make money doing it, but he already has money AND already makes a ton of money in his current job, working far fewer hours with little to no stress.
I'd bet no. He wouldn't want to. But if he has the itch, he might. Coaches are coaches because they love coaching. It takes more than loving football. He has the perfect job already for a football lover. You have to love coaching. It's very different than what he does not.