Sanders played at a high level last year and is a savvy veteran. Who replaces him? A rookie? Most rookie WR don't produce big numbers in their first year and many first rounders turn out to bust - so question mark.
Buckner was a big loss - I think they needed the money to pay Armstead- was last season the ole contract year burst or a new normal for him.
Staley was an all-pro. Trent Williams is too, but the guy hasn't played a down in what, 2 years? He's 'only' 31 but can you shut it down long term - then pop back up at that age?
They, like every team, has question marks right now. Why assume all our question marks (ILB, OL) will turn out worse for us and theirs will turn out better?