Are you concerned about church membership decreasing? Is your point that "postwar liberal Christianity" is the cause of it?
I am more concerned about how the postwar consensus has been used to dismantle virtually every aspect of what could be called a high-trust Christian society,
and how postwar Christianity essentially surrendered to this new order, replacing its own moral framework.
Feminism for a simple example. Christian morality has distinct order for women and wives. Postwar feminism says that men are evil for treating women any differently than men. Postwar Christianity surrenders to this new order, and then we get the joyful fruits of a feminized society ruled over by women, which has been a disaster for families, children, safety, etc.
But more to the point of the OP. We have a postwar Christianity adopted a new moral framework which makes "Racism" the greatest sin in all the universe.
If you want to see some of the fruits of this, we can look at the mass rape of native children by foreigners in the UK... and the basic attitude is "
sure, mass child rape is bad and we don't like it, but someone might call us a racist if we tried to stop it, so we must be tolerant" ... and sadly that is not an exaggeration. I wish it were.
We see similar scenarios in the USA. We must tolerate insane levels of crime and degeneracy. We must watch old ladies get knocked out on the street, because anyone who tried to honestly deal with the problem would be guilty of the ultimate sin of "racism". (of course there are plenty of non-White people who are in full agreement with my perspective)
I have zero doubt that the apostles of Jesus would call us all degenerate cowards for letting our society degrade to its current state, all in the name of a grotesque parody of morality and virtue that is advanced under the postwar consensus.
People may still be confused about what exactly this "postwar consensus" is. Basically it is the idea of the "Open Society"... that your society must be open to all people, cultures, religions, ideas, and that it is evil and authoritarian to try to close off your society in any way, whether physically through immigration, or culturally through adherence to a particular Christian ethic. e.g. (your an evil authoritarian and you hate freedom if you try and make pornography illegal)
Anyways, that is the jist of my concerns on this issue, hope that helps.