It's not just utility on my end; I think it would be selfish.
In the last twelve years I have had sixteen jobs. That number being so high wasn't really by choice; I've been fired and laid off a bunch of times. We can wax philosophical to the reasons why, but one thing that has become clear to me is that I'm not a terribly stable person. I am often pretty mean, short-sighted, and impulsive. When you don't have kids, those attributes are kind of considered "eccentric", but if you do that to a kid you're (correctly) considered "abusive".
It's one thing to be the primary breadwinner and have your income cut off twice a year when I only live with adults, but it's another when there's a tiny human who is 100% your responsibility depending on it. If I had a kid, it would be a purely greedy move on my end. They would be a prop, like a puppy, there to make me feel better more than any kind of altruism.
It's one thing to use a pet as a means of self-comfort, it's another to use another person.
Occasionally I will get the urge to "pass my knowledge on", which is why I will occasionally do adjunct lecturing at a nearby university. The students don't just accept everything I say implicitly like a child would, but that's alright and I don't think I would want someone to automatically believe all the shit I say.
I think even when I'm old and alone, I'll find ways to keep myself entertained.
To be clear, I'm not one of those toxic r/childfree assholes. I don't have a problem with people having kids. I was very happy when my sister told us she was pregnant. I like kids, I try pretty hard to be a decent uncle to my nieces and nephew. I just don't want to be responsible for their development.