There is no team, no coaches, no players in the NFL that starts out the season thinking this season is lost and they won't even contend for a playoff spot.
What if the Bears start out the season winning 6 of 8. And Fields sprains an ankle and Bagent is the only QB. Now some may think that Bagent can step right in without getting many reps during the week and lead the Bears to victory. Maybe he can. I have not yet reached that point, but its certainly looking more and more like a possibility. I still think there's a place for a Walker or Peterman (maybe just Peterman).
Did you notice last year that Poles didn't unload the veterans Quinn and Smith until after the Bears started losing?
Poles is doing a good job of mixing youth and veterans. Look at O-line, HB, WR, QB but probably not TE so much. Defensively, DT, LB, CB and safety have a good mix. Even DE. If the Bears had not added Walker, Ngakgoue and Green they'd be pretty much left with last year's Gipson and Robinson - even Terrell Lewis who all were near the absolute bottom of PFF grades at DE. Fortunately, at DE you can switch guys in and out.
Who says the Bears can't contend this year? If they can make the playoffs - anything can happen.