To lament the decline of cultural Christianity is to lament not simply the loss of a Christian consensus, but the loss of the social capital born of common grace that secular society was borrowing from.
Being liked is the currency of our social relationships, seen in everything from the unspoken gravitation toward one person over another at a party to the digitized tokens of attention we exchange on social media.
If the social pressures against historic Christianity do increase—as I expect they will—pastors and ministers will need a deeper doctrinal foundation, one that enables them to effectively catechize and instruct congregations embedded in a neo-pagan West.
God did not just make humans who could make culture. God specifically says that humans should make culture to reflect him as Creator.