Honestly, I think most of it is because I'm a hardcore introvert in any situation where I don't expressly sit in a seat of power. Put me in a board room and I rock, I'm assertive, and I control things. Put me in a party where I don't know anyone and I pet the dog all night because even talking to strangers makes me anxious. I don't really try to project it, but somehow I do (it's not uncommon for me to be the only person on a packed train with no one sitting next to them - and I'm meticulously clean and well manicured so it's not like I smell, lol).
But either way, AC can imagine away about "how beta I am." I'm married and have a kid on the way. In pure biological terms, I'm about as successful as I can be. Financially, I'm pretty well off too. Work wise, I've owned businesses and currently have a great engineering job. So, if this is being "beta," well, beta I be. I don't really care, I'm happy where I am. Though I agree with you - usually people who have to start going into the alpha/beta thing are just really, really insecure. I got more from Dale Carnegie than I ever got from Neil Strauss.