Just like about anything else, teams are constructed on the good, bad and neutral actions of everyone involved, seasoned with luck.
DL made some bad choices but some good ones too. Quin did a lot of things good and some probably not that much, but he absolutely squeeze almost all that was there to be squeezed.
Ownership changed, franchise culture is evolving, new alpha daugs out there, lots of things to be settled out...
Sometimes you do things mostly right for quite some time and then a couple misses/changes here and there just stuck you in the mud.
This team was constructed to go deep. They just fail at the last touches.
Don't want to be too critical on our guys.