This undermines your thesis, because it's not the mystic woo about virgin birth and transubstantiation and resurrection (which they all profess to believe in) that's important - it's the canon - adherence to which is entirely orthogonal to faith.
It can't in large parts of the US because it's a fringe minority, but doesn't it behave in the exact same way in an area where it is the dominant social affiliation?
Its rituals are just as odd and esoteric as the practices of the stranger evangelical churches.
Because this is the case, and because of the hierarchy in place for interpreting scripture and handing down sacred tradition, it becomes less likely that there will be problematic theological dilution or drift.
Biden was closest to a traditional Catholic and they *loathed* him.