The financial math ain't mathing for younger people who want to start a family. Unless you have a household income of $150k-200k (even in LCOL areas) good luck affording:
-Mortgage, especially with rates being what they are now
-Daycare (one parent can stay home but being out of the workforce for years puts you behind career-wise, plus most families need two incomes even without the cost of childcare factored in)
-Groceries
-Student loan payments
-Car payments
-Home maintenance
-Retirement funding
-Contributing to any semblance of a college fund for your kids
Parents get a break once the kids are in school, but oh, if you didn't buy a house in a great school district you've gotta consider private school, so any daycare savings now go straight back out the door. And as kids get older their extracurriculars cost more. Have fun paying for travel ball for two kids for 7-8 years, plus private coaching and whatever else parents pay for these days in the hopes their kids will get a scholarship or go pro.
Combine all of those insane expenses with a dismal dating scene and countless media outlets telling young people how awful marriage and kids are and yeah. It's no surprise Gen Z is opting out of it. And it's definitely a problem.