The kids I knew weren’t “acting like adults” in college - they were off.
Didn’t know how to hold a conversation, they were uncomfortable, and had a hard time with social cues and basic listening/including people in conversation.
If I had to speculate I’d guess they had a harder time modeling other people’s mental states along with just generally knowing less what to do - which I think comes from having less peer social exposure to learn from. This creates a feedback loop of social anxiety which can be limiting.
Part of the reason it may be hard to distinguish homeschooled people in the workplace is because they’re largely not there.
It’s hard enough to develop comfortable social skills even with siblings and a lot of exposure. I’d be worried that removing your kids from an environment where they’d get a lot of exposure makes this even harder for them in the long run.
As for homeschooled people in the workplace, my hunch is that there are more than you think there are, and you don't notice because they look like regular adults, but I have no proof! I happen to know a few professionals who were homeschooled, but I never would have known without having had a conversation about our kids and mentioning homeschooling.
I'd be curious to ask adults that were homeschooled if they would want to do the same for their kids.
I'd wonder even if it's the common case they end up perfectly normal adults if it's hard for them prior to that.
I think I'd be nervous about being able to do it effectively for my own kids (both for the social and academic reasons).
That doesn't mean I don't think it's a solvable problem and there is probably a way to create a community of people to do this well, but that might just end up looking like a secular private school.
Anecdote of 1. I have many friends who were homeschooled who homeschool their kids, and many who refuse to.
We're in the very early stages of homeschooling our kids and all we've noticed is that kids on the playground who go to school are surprisingly mean (obviously not most of them, but on average). Thanks to the internet, our kids aren't missing out on pop culture, but they're also not taking their social cues from the coolest 7 year old. Seems like a win-win.