Isn't this the line of thinking of sedevacantists and the FSSP, though they arrive at opposite ends?
The SSPX (at least historically) did not agree with either of those.
Your are correct.
Sedevacantists and conservative Novus Ordites agree on the PRINCIPLE that the Church could not have erred so gravely.
SVism --
MAJOR: Church cannot err this gravely.
MINOR: Novus Ordo establishment has erred this gravely.
CONCLUSION: Novus Ordo establishment is not the Church.
Conservative Novus Ordists --
MAJOR: Church cannot err this gravely.
MINOR: Novus Ordo establishment did NOT err this gravely.
CONCLUSION: Novus Ordo establishment is the Church.
Meanwhile the SSPX agrees with liberal Novus Ordites in principle.
SSPX --
MAJOR: Church can err this gravely.
MINOR: Novus Ordo establishment has erred this gravely.
CONCLUSION; Novus Ordo establishment is the Catholic Church.
Liberal Novus Ordists --
MAJOR: Church can err this gravely.
MINOR: Novus Ordo establishment has not erred gravely, but got it right.
CONCLUSION: Novus Ordo establishment is the Catholic Church.