In my experience, kids do make you 2x-3x more efficient, at least. You can only do so much real work in a day and you're forced to move that work into a smaller time interval. However, your mileage may vary.

I think the positive outlook given my parents simply stems from the fact that they wouldn't make a different decision if they had to do it all over again, even if it was a giant pain in the ass. It's less of an unconcious aversion to admitting mistakes and more that, after all is said and done, they would rather have their child (and the memories of them) than to spend 18 more years being childless. Childlessness is fun but it does lose novelty, and some things are worth it even though they can be hard.