I do have kids and can definitely relate to the cost they have on time, energy, career, money, cognitive functioning, social life etc. (Conversely, this is probably the healthiest I've been in my life, as running is a legitimate reason to get out the house, I'm always active because there are so many chores to be done, I've lost weight (was obese) as I need to be a good role model, we eat healthily as we need to do that for the kids and we eat together. DP and I have sacked off alcohol and other vices as we can't parent with even a one glass of wine hangover).
I got distracted from my original point there, which was going to be: I think with some parents who criticise the child free, there is an element of envy. I am happier for having children, though god knows why. By most accounts the quality of my life has declined. But I was unhappy before having children, and I feel satisfied now. I think a person is very fortunate to be able to be satisfied with their life, without having kids. For me, the burden to have kids didn't come from societal pressure (most of my friends from my 20s and 30s are child free), but most likely some biological / hormonal urges. I seriously considered not having kids for a while. And I could get quite giddy and excitable when I imagine what my life could be like without kids now (I'd be so gorgeous! Fancy gym! The clothes! So cultured! So much theatre and Michelin stars!) But realistically I'd be a bit depressed and empty like I felt before. Because I maybe do have some existential emptiness, filled up with having kids, which I'm not really sure is ethical. And in some ways the responsibility of having kids makes me a better / more functional person, I care for them better than I ever did myself, so I guess I reap the lifestyle benefits of that too.
But honestly, if you can be content without children, and don't seem to need external pressure in the form of the weighty project of having children, to force you to organise your life into something meaningful, I wouldn't rush into it.
I do envy those of you with that, but am very happy for you. And pleased you're under less societal pressure l to make choices that don't suit you than in the past.