And I don't even mean racism - say your potential candidate is older with kids (assuming you're younger) would you pass them because they cannot go out drinking with you after work (a.k.a social circle)?
That said, I agree that you want to work with people you get along with, but it has to be at work. Social circle is the issue for me.
This is, and has always been, a real problem: That your ability to get good positions is limited not by your skill set but by your ability to network.
2. The notion that companies will win purely due to skill is questionable. I would highly recommend listening to "How I Built This". Skill is a significant factor, but companies that win do not always do so based on skill.
Anecdotally, some of the best engineers I've worked with despise the networking culture and prefer to keep to themselves, while some of the most "social" and "networking" people were grifters who didn't have much skill, but knew how to appear like they do.
Not really. In my experience that is the exception rather than the rule. Especially because most people will have no way to know you have good skills if they don't already know you.