It happened before that. Roe vs Wade was a symptom, not the cause.
I suspect (and this is just me) it happened in WWI. When all of Christendom rejected Christ in order to advance a secular agenda.
Are you referring to the Fabian socialists???
They started about 20-30 years before that time, but I believe they began to rise in popularity among the academics and other receptive citizenry...
I could be wrong about your analysis...Just thought I would throw my take on your timeline there...