I think two things:
1) Life is so good and interesting right now, with so much wealth and health and things to do...that not having kids can lead to a fully lived life. This is new. In the past there wasn't enough wealth out there to live big lives, unless you were rich.
However
2) Almost everyone will not take advantage of #1 - instead, 99% of people will have quiet lives, with some highlights sure... and then die. They will be forgotten almost immediately and will not have taken advantage of what's out there.
Having kids at least assures you of an extraordinary chance to connect to other human beings, watch them grow, feel an indescribable connection to them, and never really be alone, psychically.
Having kids gives you every chance to be a hero, to do extraordinary things. Parents have that chance every freaking day. Without kids...you really have to go out and find opportunities to be a hero and do big things. Hardly anyone will.
Choose parenting.