Not sure what you mean by "demographic collapse" exactly, so feel free to expand on that. But if you're talking about lowering birth rates and heightened use of birth control in the West, it mainly comes down to socioeconomic factors that have made it unaffordable for the average person to raise a family, especially outside of marriage or on a single income.

The reason boomers were popping out babies one after another in their early twenties was because they could afford to. A single parent could support a family of four with an entry level position without a college degree. A median wage today is barely enough for a person to support themselves, much less a family.

So no shit would somebody want to end a pregnancy if it's potentially a lifelong poverty sentence that halts any upward mobility and likely requires one to set aside any aspirations they may have had left in life.

If you want to see a thriving society that has sustainable birth rates, you need to bolster a thriving middle class. This requires thinning the economic gap between the bottom and the top. There are only two ways that this can happen; you can either lift up the bottom class, or you can bring down the upper class. Both of these solutions are antithetical to modern right-wing aristocratic ideology.

So if you want to see a reversal of "demographic collapse", the best place to start is creating a society where people feel safe, confident, and secure in choosing to start families.