>>60895428 (OP)
Most people who make it married and had kids young (by today's standard - so around 25).
The wife is the accountability that keeps you from going into unemployed NEET-mode and playing video games whacking off for 6 month intervals just because you can.
The kids are the alarm bell that makes you really pull your shit together.
All you end up missing out on doing so is the excessive levels of partying and degeneracy single 20-something professionals get involved in that often ends up ruining their lives even if they don't know it.
By the time you're in your mid/late 30's, the kids kind of take care of themselves, you just need to pay for a lot of it. But you're probably doing so because you've been working/progressing instead of playing video games and getting drunk or doing drugs. Having kids/wife also makes successful people trust you more. It's better for your career.
Being single in your 30's as a guy makes people suspicious of you, and does affect your upward mobility.