The defense has done well against 4 decent offenses in a row.
It also helps that the offense can sustain drives and give the defense more rest.
This 2025 ND team reminds me of 2002's USC team, where they started out slowly, losing early to a couple of very good ranked teams (Washington State ended up being #10, Kansas State was #6). They were reeling, and the "fire Pete Carroll" chat started buzzing.
They got their act together, and steamrolled everyone in the 2nd half of the season, with 5 of them being ranked teams.
That was the 2nd most crushing feeling for Lionel Tyrone Willingham's inaugural season as ND's coach (BC loss was much worse feeling), since Carson Palmer carved us up like a Thanksgiving ham.
At the end of the season, USC was in a position where they could have been the best team in the land, and under today's playoff rules (or even the 4 team playoff), they could have certainly made a statement.