Sometimes the stars align just right.
Wentz was having a MVP that year before his injury (and did get his team to the playoffs), and by luck or the stars, Foles did play with balls of steel during their playoff run and played exceptional for that time.
I honestly think Foles should have retired after the SB win and leave on a high note given his time in the league at that point. He's mediocre at best and runs in streaks. Problem is, given a whole season, that may only equate to 8 wins. I'm honestly not a fan of Dak for numerous reasons given his time with the team, but he is by far a better QB than Foles over the long run IMO.