Having a great Pres of Ops/GM is huge don't get me wrong. The Cubs stunk it up before Theo came in and what Belichick does year in and year out is impressive. Having said that players win championships. Without a couple of starting ace pitchers or a franchise QB, the chances of winning a championship are slim. Any competent GM (meaning good, not great) can get good players to build a team. Grigson sucked so now Ballard is a God compared to him.
Tom Brady isn't your average QB, he is one of the best ever if not the best of all-time. People see how great Belichick is and think he can plug in any QB and win SB's. No he can't, he can win a lot of games and proved that with Cassell in 2008 but winning 10 or 11 games in the regular season and winning SB's is a big difference. Take Brady away and Belichick IMO would probably only have 1 or 2 SB wins. Belichick is that great but Brady is super clutch in the playoffs.