In theory, I agree with you. But sometimes, if a game was close and the losing team plays a more difficult schedule throughout the rest of the season -- and has more marquee wins -- they can pass the team that beat them. I think this happened between TCU and Baylor around 4-5 years ago. TCU was ranked higher by the playoff committee despite a close loss to Baylor.
Also, it happens in the NFL quite often where one team sweeps 2 games from a divisional opponent, but loses the division title because they ended the season with one more loss. The head-2-head matchup(s) only matter when things are equal. But if one team's resume separates from the other, a head2head match up doesn't come into play. A lot of people don't seem to understand that.
For example, let's imagine if Folsom pulled off an upset against DLS that went down to the wire. And then DLS plays the likes of SJB, Euless Trinity and Bishop Gorman and wins all those games (assuming all 3 are elite) while Folsom plays nobody else of consequence. DLS would almost assuredly overtake Folsom for the Open bid. That's how it works.
