If you want to believe that injuries to Amendola and Edelman are what derailed the 2013 and 2015 seasons, then you weren't paying attention.
2015 was derailed by every Offensive lineman with the except of David Andrews and Chris Barker suffering an injury and missing time. The Pats had 16 different O-linemen that year. When you have to start 5 different LTs, that's a bigger issue than your receivers..
2013:
Amendola missed ONE game that the Patriots lost.. That was the 27-20 loss vs. the Jets in October.
Edelman didn't miss any time in 2013.. Played 16 games, starting 13.. Edelman wasn't used much against the Steelers, Panthers, or Dolphins.. The Panthers and Dolphin games were losses.. Amendola played in both..
Now, if you meant 2012, which was actually 5 seasons ago.. then you might have a point.. But, you're also talking 5 years ago. And that is the season they lost Gronkowski to a torn ACL due to a low hit by TJ Ward.. But that is also the year that Stallworth played one game, caught one pass and then was lost for the season.