Not surprising, because Brady is the better quarterback. My position has always been: 1. Brady is better 2. Manning is really, really good, and was not far behind in their respective primes. Switch Belichick and Dungy and you probably switch the results of the playoff games. 3. Brady benefits from having the GOAT coach/football mind (particularly in big games) 4. The disparity in SB wins is attributable to a variety of factors, including the other 52 guys on the roster, the coaching staffs, the playoff opponents, and HFA.
It's not that your points are completely invalid, but you may want to consider looking at it a different way. Both teams had their pluses and minuses. Sure, overall Brady has had an overall advantage with BB, although Manning has had some great talent around him and ended up having a lot of elite defenses in Indianapolis from 2007-08 and Denver. Brady's defenses were generally good, but he had his share of clunkers and hasn't had a truly dominant one in a long time. Both the Colts/Broncos and Patriots were dominant teams that almost always won over 12 games. I find it hard to believe there was that great a difference to explain the huge discrepancy. Rather, though, both quarterbacks have found themselves many times late in the game with the season on the line with vastly different results.
Manning finished 14-13. His only two game winning comebacks came in 2006, against a gassed Patriots defense devastated by the flu (plus a zillion other factors in his favor, such as Reche Caldwell), and in 2015, when his "game winning drive" consisted of a fluke fall-down and get-up, and then a long touchdown run on a handoff. He did not throw a single game winning fourth quarter TD pass in his entire postseason career, despite having many, many opportunities. There are too many games to point to where he just couldn't get it done when the going got tough. Games that come to mind where had not one but multiple opportunities to come through were several games with the Colts against the Chargers (one where he couldn't outduel Billy Volek), against the Steelers in '06, the Super Bowl 44 pick-six to Terry Porter, Ravens '12 (OT loss where he just completely fell apart), Colts '14. When he struggled in those playoff games, he was always unable to find that extra gear with the game on the line, and these were really memorable losses because usually that's where great ones come through. Let's say that just 4 times, he had put drives together to win games, which is probably about consistent with his regular season performances. 18-9 is certainly a different sounding record.
Brady is 22-9. His record would likely be close to, or under .500 if he had struggled like Manning in close postseason games. While Manning's postseason simply contains very few dramatics down the stretch, especially in those "grind it out games" where the defenses are very tough, it's hard to find games where Brady failed to win when it was close. The two Giants games he played in, he did bring them back. Were there any games the Colts even blew after heroics where Manning gave them the lead? I literally can't think of one. Brady's greatness and superior record is best explained when the game was on the line. The Tuck Rule Game, Super Bowl 36, Super Bowl 38, Chargers '06, Ravens '11, Ravens '14, Super Bowl 49. That's seven games with remarkable clutch performances with the season on the line; the two Giants games would make nine if the defense held them. These weren't dominant games where the supporting cast and coaching staff made it a contest; Brady was the difference. Manning's career was filled with those opportunities, but he didn't carve out a lot of memorable moments.
Winning those playoff games in the fourth quarter is what makes legendary performances, and Brady's career is overflowing with them. With the exception of Manning's 2006 comeback, a game where he put them in the hole to begin with, does he have any? Is there a single defining moment of his career where he really was incredibly clutch with all the chips down? Even his Super Bowls were unremarkable and carried by his defenses. This is really the major difference here...it's a lot simpler than just coaching and supporting cast arguments. At the end of the game, both teams have really seen it all, and it comes down to poise, guts, and winning. Brady is a legend and the best ever. Manning is an all-time great player who struggled often when his team most needed him.