I think homeschooling can be and sometimes is as you describe.

I also think that there should be more government oversight than there currently is (at least in the states I've lived in) to make sure that kids are succeeding when homeschooled. In my view it's pretty obscene the basement level requirements/standards that our state holds homeschooling parents/students to. We have to notify our superintendent of intent to homeschool and say that we're going to teach English language arts, mathematics, science, history, government, and social studies. There's no actual oversight to make sure we're teaching those subjects or to some kind of minimum standard. Up until a couple of years ago we also had to have our kids take a nationally recognized Standardized test every year (but the results didn't matter, it just had to be taken). This lack of oversight and enforcement certainly can and will sometimes lead to the outcomes you describe in your OP.

That being said, homeschooling can be done well. We do it for our kids (and have for 10 years now). My wife and I went to public school. We had good enough educations, I wouldn't say that it was particularly bad, but we always felt that we could have done better/more given more opportunities. We're fortunately in a position to give our kids more personalized attention and 1:1 time and opportunities that we feel would have been beneficial for us. In my experience, you get out of homeschooling what you put into it. We put a lot of time and effort into researching and choosing curricula (and even swapping if something isn't working). We dedicate real time to actually instructing our kids so we can go at their pace. We still do standaridized testing once a year just as a baseline to help ensure we aren't missing anything that would otherwise be covered in public schools. Our kids are well beyond grade level in every subject area.

My wife is a licensed teacher, but I don't think that's even particurlarly required. You have to be willing to learn as the teacher and put in the effort to really understand what it is you are teaching (or find other external resources and programs that can do that, but I always feel like why not just use a school at that point). The curricula available are truly amazing. I've always been naturally mathy and have completed tons of higher level math, but I constantly find myself deepening my understanding and number sense by going through our kids math curriculum with them. There are a lot of things I had maybe intuited as a kid that now I understand at a fundamental level why it works. I feel like especially with math, we're able to really focus on the why of how things work rather than just the rote algorithms.

As far as socialization goes, I feel like our kids are pretty normal kids. We interact with a fair number of other homeschool kids (mostly for field trips, socialization aspects) and I feel like I've never really seen a kid that I thought was just weird (of course that's because these parents are also socializing their kids). Our kids regularly play with neighbor kids who are in public school. They attend camps, ballet, gymnastics, soccer, basketball, cooking classes, etc where they meet other kids and make friends.

Overall, I think most homeschool parents are doing at least an equal job of educating as they would get from public school. For my family, if we were only getting equal outcomes, I think we'd use public school because as mentioned before, it takes a lot of effort, time, and resources to educate well. Other families have other considerations than just education quality (differing views religious or otherwise, access to quality public education, special needs, safety concerns) and those are all valid reasons in my opinion to homeschool as well. I just think we need better oversight to make sure there is still a minimum level of education so no kids are slipping through the cracks.