The major cause for imprisoning toddlers and even young kids these days is the risk posed by vehicles.
My parents' generation grew up in a developing country where the villages did not have paved roads, and 90% of traffic was very slow moving ox pulled carts or motorcycles, and maybe a small portion of small cars. The grandparents' generation all had 4+ children, and women were not staying home to watch the toddlers. The toddlers were supervised by older toddlers, who were in turn supervised by older kids and they all just ran around the village all day until it was time to eat.
Outside of caring for infants, the mothers had many duties such as working in the farms, factories, cooking, and cleaning, similar to men. What they did not have is legal ownership of capital and sufficiently high income streams to go their own way if they wanted.
But none of this is applicable in modern US society.
I'm not sure that's the case. They demand lots of attention, sure, and it's often hard for adults to say "no" as they leverage their ever-gushing cuteness.
They do need a certain level of focused attention with adults, but overdoing it spoils them. Have friend and relative kids come over; most kids are social and occupy each other, learning social skills in the process. An adult does need to check on them every now and then to make sure they are not lighting the cat on fire again. If they seem too hyper, put them in sports, and rotate the driving with other parents. Boys especially need hard physical activity to milk their wiggles out, or they will light the cat on fire.
Your problem wasn't that you were socialized "late", but that you were socialized in a way that didn't allow you to compete in the world outside of the circumstances of your upbringing. If everyone else was socialized like you were, you probably wouldn't have that problem.
The reason I don't like recommending school or daycare for young children is that although they learn superior marketable social skills (lying, deference, aggression, status gaming, etc.) early on in life, for the most part they think and behave like inmates do. I cannot deny that those who don't go to school find themselves at a social disadvantage, but I do not think that those who go to school are "socialized" in a healthy way.
But that aside...
So what would you recommend? Seems like those skills, though you don't like them, are currently useful in college and the adult world as well. But often quite lessened! Adult friend relationships tend to be healthier than high school social games!
And with the particular case of teenagers, it's often all they have. Tiny aspects of social standing are important because there is often nothing actually meaningful that they can contribute to or do with a near-term payoff. So it's either grind in the hopes of a payoff when you're 20-something and have graduated college, or play vicious games for short term social prizes, or both.
I would definitely be in favor of trying to figure out how to make the late-teenage years more "meaningful" but I think tearing the rest of the system down is not realistic.
I agree with everything else you say.
The fact that teenagers only have a hyper-competitive useless social atmosphere is a quirk of the past 50 years, and hasn't been true at any other time in history. Compare the required responsibilites and daily life of a Pueblo 16-year-old in the pre-Spanish 1500s, or even a poor English 16-year-old in the early 1900s to those of a 16-year-old in school in the modern U.S. Each of the pre-modern lives are far less comfortable and more dangerous, but far more meaningful to those who own them.
I don't mean to say that we should tear the system down, or that a modern 16-year-old should wish they were a Cornish coal miner during WWI. However, when the system is entirely made up of people who believe that the system is inevitable and the only way to live, meaning becomes very difficult to come by for the children it institutionalizes.
For an individual child/teenager:
- Friendships or at least informal apprenticeships with productive adults - Martial arts (those that are actually effective in the UFC, not flashy arts) - Creation of products and/or art - Strong musical tradition - Knowledge of one's lineage, ancestry, and family history