I think most of what you say is accurate. I don’t know that his issues were learning the scheme as much as he isn’t a crisp route runner. But at the end of the day you are pretty much echoing what I’m saying. It isn’t a talent deficiency keeping Dez at home, it’s all of the non-talent issues like his inflated sense of worth, issues in the locker room / sidelines, social media, etcetera. If he didn’t have those he would be on a team right now regardless of whether he runs the right routes all of the time. A guy like Rodgers could get a lot of mileage out of Dez as a #2 or #3 option. He’s essentially his own worst enemy.
The Cowboys are partially responsible.
Dez had his 1st training camp when Wade was still the HC. There was zero discipline on the team and by then the inmates were running the asylum.
Garrett brought better discipline but it took a few years to dump the bad apples.
If Parcells or Jimmy had been the HC, Dez would not have been allowed to get by with all of his nonsense.
It might have been a bit better if Dez had arrived a few years after Garrett became HC but Garrett's primary method of instilling discipline has been to avoid having problematic players on the roster and instead get college team captains.
I would love to have seen Dez play for Jimmy...
Under Jimmy, he would either have been traded away after a couple of years or would have been an All-Time great WR.