He was drafted to a team with an incredible team (especially defense) and coach.  Many organizations would never have given a 6th round draft pick a chance (and injury helped with his chance).  His first 3 Super Bowls were mostly defensive led (not many other teams beat the Rams with the GSOT with just 20 points that year). 

All of that led to great success and allowed Brady to become what he is today. 

Another example is Cleveland.  Do we really believe every QB they have drafted over the last 18 years has been bad?  I don't.  But the organization is inept leading to failure by all of the QBs.  If Brady was drafted by the Browns in 2010 he would have failed also.  It doesn't make Brady any worse of a player or any less in my eyes, but certainly circumstances can make all of the difference.