Background
A number of myths and misconceptions surround what constitute reasonable expectations of drafted players. Do half of all first-rounders bust? Are players drafted after the third round unlikely to contribute more than a few games? Should each team be able to find three starters every year in the draft? Each of these questions depends largely on era, and the rookie salary schedule initiated in 2011 significantly changed how teams handled draft picks.
Additionally, after the initial 4-year period, players are typically no longer on said price-controlled contracts, and a 5-year window provides for the ability to check on whether or not players were deemed successful enough to earn reinvestment from NFL teams (be it the initial drafting team or one of the other 31 franchises).