They have a pretty strong FO. Cowboys have been one of the best drafting teams in the NFL for a decade. They also make pretty good FA decisions. Overpaying Zeke is the only notable mistake they have made. They overpaid Dak, but basically everybody overpays the QB, so hard to knock them for that.
The Cowboys haven't had a good run because they've been plagued by big injuries every year. I remember a stretch where Sean Lee + Tyron Smith + Dez were like 18-1 together over like 3 years, but two of them were usually missing. Now Lee and Bryant are done, but it's been kinda the same story with the new stars. Jalen Smith already cut because of injury. Zeke isn't usually 100%. T Smith continues to get hurt all the time (and the Guard, I forget his name) and it totally changed their fortune because they went from top 5 linemen on the left side to below average.
They just kept on drafting well and that's why they have a good team this year, even without T Smith, they lost Cedrick Wilson's son, and Amare Cooper plus Gallup and Dak's injuries. Dak and Gallup are back and Smith is supposed to come back. I know they think this every year, but might finally be the Cowboys year.