I've thought about this and while I agree with you completely, I think the reason why is not just society at large. Externally what most people see is the time suck, money suck, and frustration with teaching behavior, fixing bad behavior etc.
What's so easy to miss is the immense feeling of love, of being needed, of being loved, that words can't describe. I frequently tell people I feel like the grinch after he discovers Xmas - my heart is three times bigger. But you can't really see that it's just a feeling I carry with me.
You don’t need children to have these sorts of feelings, unless you can only get them from some small people who don’t have any choice but to love you.