> Parents are plenty qualified to take care of their kids.
Are they really though? I mean, I was raised by mine, and I've done well enough for myself, so that system can't be too bad, and most of the rest of humanity has also been raised by parents, for since... before there were humans. But if we look at this from first principles, it doesn't actually make sense. First, we let just about any random pairing of two humans, one of which has a uterus, can be a parent. Think of the most average person you know, then realize that half of everyone is dumber than them. Then put them with someone else that's just as dumb. Now give them a baby. And then add sleep deprivation on top of that. Seriously, it's a wonder that the human race has managed to survive this long.
Experience is another thing. Even the most talented brilliant person needs to practice to reach their full potential. Raising a child as a skill is no exception. So we're gonna have absolute amateurs each raise a child, and then, most likely, throw all that learning and experience they did away and not have 10 more. Practice makes perfect, so let's not do that.
What sort of training do we give parents before and during their parenthood? Before we send people off to do a job, non-stop for 18 years, how much training do we give them? Four dedicated years of college with plenty of lab and field work? Not in the slightest. Parents are expected to fund their own education for this job.
Finally, the incentive structure is misaligned. Children don't make any financial sense, since the passage of child labor laws. Don't get me wrong, those laws are a good thing! But from an economic intellectual standpoint, it doesn't make sense to fuck up your life like that. Birth rates in the developed world reflect this. It's obviously a problem though, because children are our future and without them, humanity dies out in a generation. So omg holy shit, have kids. Societally, we need them. Society's only allegiance is to it continuing, and it doesn't without kids. Unfortunately they can't show an ROI in a single quarter, so we'll have to figure out a better mechanism for it, but for something so important, our future, shouldn't we want our best and brightest people on the problem? Yet we don't spend rationally. In the US, the school shooting industry (what schools spend on security in response to school shootings) is a multi-billion dollar industry. That money would be better spent on counselors and on the teachers. But back to my point, we'd rather have unpaid amateurs raise children on their off hours, instead of hiring professionals to do it? And make them pay for it as well? Make that make sense!
The failure modes are known. Children get molested, abused, killed. Raised wrong. Those are corner cases, for sure, but I wouldn't argue that those parents are qualified to raise kids.
Still, that's how we've always done it, and holy shit kids are cute, and you love yours, so of course we think parents are qualified to take care of kids, but we don't actually do any qualification except in the worst cases that we know about. Everyone knows somebody that knows somebody that had a bad childhood and didn't get the government called on them though.
Children being raised by parents we assume are qualified is how we always done it, so the system works well enough, because humanity hasn't ended. But if you were designing a system, you wouldn't do it that way.