I would in so far as until Biden, we went 60 years in between a Catholic (roughly 25% of the population) was elected. But that's not the issue here. You're saying that the "mainstream culture" is white Evangelical and I'd argue that it isn't; that White Protestants are divided (Episcopalians are disproportionately influential and represented, for example) between mainline and more Evangelical groups. That said, if one were to lump in Catholics (not quite accepted, as you put it) with mainline Protestants, the Evangelical influence is diminished. Throw in Jews and Moslems (3% each -or 6%), some Buddhists and the unaffiliated. and White Evangelicals aren't that much of a force. For instance, New England has a very WASPY and disproportionately influential influence on America. It's definitely not Evangelical. Sorry