The argument can be made that abortion does not threaten a culture. That it is only an individual choice.
I almost wish we could conduct experiments, Culture A without abortion and Culture A with abortion, and then observe the differences over time.
I do believe they would be different.
I can think of differences that are reasonable to expect once fertility is controlled. I would predict a lessening in the valuation placed upon marriage. I would see a callousness develop toward human life.
Those off the top of my head. Can you see any more?
Any culture would be better off without abortion or drugs (including alcohol). But for most cultures "without drugs" is not an option; even many despotisms have drug problems (Singapore's repressive regime appears to be an exception). The enrichment of criminals that is our War on Drugs' only undeniable accomplishment is certainly harmful to our culture.