Nick Foles is currently the no1 rated passer in Eagles history, the No1 winningest playoff QB in Eagles history, and the no2 rated completion % passer in Eagles history. And he's the no1 rated all time NFL playoff passer in rating and completion %, ever. Throw in a superbowl MVP on top of all that.
As an Eagles fan, to me, he has earned the job.
I SUSPECT that what will happen is Wentz wont be ready for week 1, and Foles will start the season as the starter. If he plays really well, he'll keep the job. If he's just OK, or bad, Wentz will get the job back when he's ready. That has happened many, many times in NFL history, with the most recent example being Teddy Bridgewater/Sam Bradford/Case Keenum in Minnesota.