The Cowboys Dee rarely "tackles the ball", or tries to punch or strip it out. They should though, since they're good at gang tackling.
And for INTs, we need DBs to be looking back for the ball. Cowboy defenders rarely look back to make a play on the ball, they just play the receiver's eyes and hands, and try to knock the ball out as it arrives.
So, to me, this is coaching. Better coaching would teach better techniques. Or we need to pick DBs who have natural ballhawking capabilities, not simply pick good "cover guys".
Most turnovers in the NFL are intentional, some defender makes a great play on the ball. The Cowboys don't have those kinds of players. And that's an issue.