So, sometimes record is important, such as when the 7-9 Seattle Seahawks get in, but sometimes it's not important, such as when the 14-0 Boise State Broncos don't. And Boise State would never be able to schedule Ohio State, etc, as their non-conference games...Ohio State wants to sweep their non-cons, and playing Boise State might screw that up. It's a Catch-22.
Why doesn't Boise State schedule Ohio State? Because Ohio State wouldn't want to schedule Boise State. In the NFL, the schedules are made so that every team plays essentially the same quality of opponents: every team plays a team that was first place in a division 4 times, a second place 4 times, a third place 4 times, and a fourth place 4 times. Division winners get in to compensate for different divisions having different strength, and wild cards get in to compensate for some divisions having multiple very good teams.