I think these theories were always more sophisticated than religions. And the work of ancient philosophers is still not completely outdated, e.g. Aristotle's logic holds up, albeit in a limited domain. Moreover, the former theories have since further increased in sophistication, while religion didn't get significantly more sophisticated.

Though I admit your point is a good one and not so easily refuted. In general it is known as the "pessimistic meta-induction": Theories from the past were wrong, so we should think our current theories are wrong as well. See

https://plato.stanford.edu/entries/realism-theory-change/#Di...

https://plato.stanford.edu/entries/scientific-realism/#PessI...