In the big scheme of things that's probably money well spent for a network to lock up a guy to represent them for a game that dominates viewership. Tom's a smart dude and I don't doubt that he'll be very good at the job. QBs in general are the best choice because they know so much schematically. If I'm running a network I want either a QB or a cutting edge type HC in that chair and you're gonna have to pay to have someone you want.
What will be funny is if Tom plays another 5 years. But either way the network has shown its investment in him so it might end up working out for them if Tom's exceptional at it.