Under normal circumstances, the Cowboys would have played their final preseason game against the Texans last night, and a bunch of players at the very bottom of the roster would have gotten extended playing time in a Cowboys uniform.
But even without that final game, the Cowboys have already played in four preseason games, have had 22 official practices in training camp, had 12 days of OTAs, and did a lot of other work that doesn't show up on the official calendar.
All of which gave the coaches, scouts, and front office personnel ample time to evaluate the entire roster before the Cowboys and every other team will have to finalize their 53-man roster.