Jason Garrett has been Dallas’ head coach since Week 10 of the 2010 season when he replaced Wade Phillips. In that time, the Cowboys put together the best offensive line in football for a time, assembled the New Triplets with Dak Prescott, Ezekiel Elliott and Amari Cooper, and had enough defensive personnel for success at the highest level, depending on the season. On its face, Garrett’s 83-66 regular-season record isn’t bad, and his 2-3 postseason mark is far from the worst. But unless the Cowboys win a Super Bowl under his watch (they’re currently 6-7 and trying to win the NFC East), Garrett’s tenure ultimately will be considered a failure by the one person whose opinion matters in these matters — owner Jerry Jones, whose team hasn’t won a Super Bowl since the 1995 season.