The Head Coach isn't the Cowboys biggest problem, it's that they have no foundation of Players to build up on and give hope.
There is no Depth at Dline to build on. We are likely to lose our starters, Osi and Gholston, in Free Agency. They aren't great players but they were the best we had.
The CB depth is non-existent with Diggs likely out next year, and Bland is our only good CB.
Jordan Lewis is a Slot CB and will likely be in demand in FA.
The Safeties are pedestrian to put it kindly.
The Oline is Average at best.
Cee Dee is our only legitimate starting WR. We have a bunch of 3's and 4's but no 1B or 2's on the roster.
The QB is paid as Elite but he is no where near and is often injured.
At every level, there is no young talent waiting to take over and fill the gaps, the cupboard is bare.
The team that doesn't play a big role in FA likely won't again and given the Cap commitments to 3 players paid at the NFL Highest, there is no money to save the day.