Patrick Boyle has looked at causes of decline in the total fertility rate around the world and concluded reduction in the formation of couples (married or not) is a major cause. https://www.youtube.com/watch?v=ispyUPqqL1c
https://www.ggd.world/p/the-global-collapse-of-coupling-and
I wonder if the ultimate cost (in lives never born) of technologies like smartphones and Tinder will be. If a significant part of the entire youth cohort never learns to interact with the other sex in the real world, we might be looking at a pandemics of loneliness - and at subsequent global birth deficits in eight to nine figures.