Homeschoolers aren't having these worries.
It is only worse between the ages of 11 and 17 because segregating children into same aged packs, treating them like prisoners, marching them about to the sound of Pavlov's Bells is and UTTERLY AND COMPLETELY UNNATURAL WAY TO TREAT CHILDREN! ( Yes, I am shouting.)
I don't think this is exactly true. Good social skills are very valuable at every stage of life. They may not be the whole main event, but they are important. Brains are important, too, but it's not the whole main event either. It's strange that this is presented as an either-or proposition. The two skillsets are not mutually exclusive at all.