Maybe for you that is life's purpose. But for others, it's not. We humans have many different higher purposes in life. Some have kids, others make society better, or any number of reasons.

I wouldn't advocate someone to have kids if they're not best suited for them. That doesn't do the kids any justice. Nor would I advocate that we should have only one higher purpose in life. That's a little narrow-minded to other purposes that may exist.

Different strokes for different folks.