Butler had that great Super Bowl pick but he's had hands of stone ever since. The odds he'd produce a game saving pick were minuscule. He basically never showed that ability ever again.
It was a weird decision to bench him all the same, but what killed the Pats were their weak front 7, especially the linebackers. The Eagles passing plays were set up by their ability to completely embarrass the Patriots front 7 with the same simple shotgun run concepts over and over and over again. They were slow, soft, and constantly getting out of position from biting on even the most basic play fakes. Losing Hightower basically made the whole unit implode, it was like watching the Cowboys defense without Sean Lee.
The trick pass to Foles was neat and would probably burn anybody, but 99% of what the Eagles did was their bread and butter plays, and the Patriots front 7 simply couldn't compete. Belichick understood what was going on but his linebackers especially simply couldn't execute.