Maybe young people don't want to have children and start families today, because they have been demoralized by never ending self-judgement and comparisons with what they see on media (both mass and social). If you think you need it "all" and the "all" is the style, the clothing, the traveling, the cars, the sex life, the house, the career, the income, of the most successful people you see online, and not among your own community and your peers, it might zap your morale enough to curb any will to reproduce or settle down.