they got a good system with the perfect QB for it and got rich. you become a dynasty by consistently winning and then having everyone coming to you begging for scraps, wanting to get raped by you in trades.
You have an interesting point here especially considering that the Patriots already had their franchise QB before picking up Brady. Though I don't think they really managed to get the system running as they have it going now until after the dismissal of Bledsoe.
they got lucky in finding brady and the took advantage of the opportunity luck brought them. we're getting lucky this year. opportunity knocks so infrequently it would be foolish to pass up on it now.