Long story short, the reason why so many players in the NFL, including the super bowl winning Patriots, have a load of 3 and 2 star players is because there are so many of them coming into college.
Just look at the 2016 pro-bowl - 44% of the pro-bowl players were 4 or 5 star players in college even though they typically only represent 9% of all recruits.
Meanwhile 3 stars account for 33% or pro bowl players, even though they represent 33% of recruits. So basically you are 4-5x more likely to be a pro-bowl player if you were a 4 or 5 star coming out of high school than if you were a 3 star.
Gets much worse with 2 star players - Compared to a 2 star a 5 star is 66x more likely to be a pro-bowl player than a 2 star player.