Which are you referring to?

I’m referring to western civilization, which has been broadly Christian since Emperor Constantine (the 300s).

> Religion, all religion, had been a drag on progress

That’s a bold claim - are you sure that your fast-moving atheistic society would sustain itself? Prominent recent examples such as the USSR have failed spectacularly. Cosmopolitan societies like ancient Persia were overrun by the religious - ie they were outcompeted. Europe too, would have been overrun by Islam, had the Christian kingdoms not banded together in the middle ages.

Certainly it’s possible, but the absence of evidence confirming it is stark to my eye.