The cap hit is too great and his perceived value is to low to make trading Wentz before the end of next season anything more than an utter disaster. I think he stays. Yes, he could be the costliest backup in football history, but they will pay about as much to have him on another team.
I don't see it as being at all impossible that Wentz is the Eagles' starter next year. In the season after he signed his big deal, Pat Burrell looked like a lost cause. He rebounded the next season. So can Wentz. Two things need to happen for either Wentz or Hurts to succeed (and survive physically) next season: we need to add a stud offensive lineman and a stud WR. The Eagles offensive roster this season was ridiculous.
For Wentz to succeed he needs to be willing to change his approach: accept the plays the coach calls, accept that he has to get the ball out quicker. stop playing kamikaze football, and calm down and get comfortable again. He will need both better receivers and a better OL, as well as some different play calls to be able to settle down. But even if he gets those, it will require more maturity on his part.
Hurts has been exciting, but he's done it on his youthful mobility and enthusiasm. Wentz once had that. To me, Hurts has yet to show he is an adequate passer. After multiple seasons, Wentz has also not shown that. It's possible neither of them is a long-term QB
I just don't think it wise to trade such a costly player (cap as well as actual $) at the low point in his value.
If Wentz can't stand to return and compete for the starting QB job (realizing that Hurts is going to get more game time than he did prior to Wentz's benching) that's just tough -- he signed he big extension, which he wanted, then stank this season. If he doesn't feel he has it in him to come to camp and compete for the starter's job, then he should have his agent determine if he can renounce his contract and become an unrestricted FA, with the Eagle's permission. It is unrealistic to expect the Eagles to pay him the big $ to play for another team.