well, he had help from #4! Seriously, the whole talk of system QBs over the dynasty was based on the fact that we had few Pro Bowlers, not loads of talent as you suggest. Its actually the reverse of your argument. We had little marquee talent, which is what has made TBs accomplishments that much more impressive. Now that he has such weapons, its blitzkreig and his numbers are eye popping.
The system QB part comes in to play when you consider TBs smarts. That he has adapted to every different gameplan that BB has laid in his lap, which is no small feat when you've had such limited breakout talent. The dink dunk, WR screen in place of a run game, the possession drives...all of these required TB to process decisions instantaneously- which is where he excels. He is a cerebral QB on par with Joe Montana.