“In this regard it is interesting to examine the history of theology in 19th century Britain. We see Christians slowly giving up their Christian identity, and adopting the phraseology and posturing of deists and monists.”
Yet there were also, in those days in England, great theologians, patristic theologians really, bishops like J.C. Ryle, who likely would have agreed with your observation, btw.
As for reaping today what was sowed then, I think you are exactly right, but our problems in the West go back further than the 19th century, to the enlightenment at least.
The Western Civilization took a wrong turn about 500 years ago, with the Plague, the Reformation, and the abuses of absolute monarchy. We shall have to backtrack and find the right direction out of the Middle Age, I think. XIX c. was a mixed bag: for the root of the decay one has to go deeper back, and for the worst manifestation of the rot XXc was scarier.