I can at least often an anecdote from a homeschool to perhaps change your view a small amount.
I was homeschooled throughout all of high school. I have met many homeschoolers, some who were homeschooled throughout k-12. Intellectually, they've all been some of the brightest people I've ever known, and a lot of them have grown up to work very valuable jobs. However, I feel obliged to agree with you on your point concerning social development. While the extent is not always severe, a lot of the homeschoolers I've met have been stunted socially by the experience. It all depends upon whether or not their parents fostered social development through extracurricular activities like sports, arts, and science. I was given a wide range of opportunities while I'm homeschooled, so I had a very active and enjoyable high school experience.
You mentioned yourself concern for our educational system. Coming from a US perspective, while it seems farcical to give up a decent-to-excellent public school education in favor of being schooled independently, it sometimes allows for the children to broaden their horizons. I left brick-and-mortar school because I wanted to spend more time studying scientific topics that interested me and I wanted to explore my field of interest early on (and allow it to organically shape itself) rather than be trapped in a school building for 8 hours learning the same things as everyone else (which is not wrong for everyone, and is very beneficial to some).
I will continue to reiterate that the educator is an important factor here. My family is secular and I was raised to think of everything around me skeptically and logically. I was encouraged to read about different issues and viewpoints and never discouraged from shaping my own. I joined a homeschooling speech-and-debate team in my sophomore year, which not only exposed me to different opinions but taught me how to accept them civilly and learn how to counter them with my own critically thought out opinions.
I've been able to forge many relationships with both teenagers my own age and wise adults through my homeschooling experience. I was heavily involved in drama and theatre throughout my high school homeschooling experience and met and worked with many adults doing that. At the age of 17 I started giving presentations on 3D printing technology and engineering and speaking with adults about innovative technologies and how the technologies that our lab uses can help their company.
I started college when I was 16. This would not have been possible without my homeschooling. In my opinion, public schools can often "hand-hold" a bit too much by not allowing independent study. Sometimes this hand-holding is necessary, but it can be detrimental to the independent learner. Since I started in high school, my parents did little more than keep track of my progress and encourage me. If executed correctly, homeschooling from a young age can grow a child into someone just as independent. It's who teaches the child that truly determines how well they will fare on their own one day. That's one of the reasons I support higher wages for k-12 teachers in the United States.
I have just turned 18 and I've been in college for two years. I will be leaving in the fall to attend a top university in my field (chemical engineering) and I will only have two years left to complete. I maintain a high college GPA as well. I have worked in 3 labs since my junior year of high school, I've taken up a dance, performed in musicals, and participated in tons of volunteerism (as a way to reach out to others after leaving public school). I can honestly say that homeschooling has not stunted my growth, and if you take the time to actually meet some homeschoolers, you'll see that most turn out alright.