I have no kids, but I do not think of it as an 'inadequacy.' Sirloin, I think you are too hard on yourself.
1. I'm a full time college teacher, 80 hours a week, and it's a big job in my view, to help really screwed-up immature high school & college kids develop some character and personal responsibility. I clean up what the parents, many of them with a few divorces under their belts, have done (or not done) for their children. If (my husband &) I had kids, it would be extremely time consuming to do well - and I could not help make a big dent in the problems of delinquency and irresponsibility I help to correct every year with hundredss of young people in their teens and twenties. So, I'm very happy with my decision. Much happier, than if I'd had 1 or 2 children. You can't do everything well (have kids, and work full time). You must make choices.
2. We have 6.5 Billion people on the planet and with that has come stressed economic resources, crowded schools, housing shortages. I think we have an implicit "no vacancy" sign out at the moment -- population growth is a serious matter which we should all think about seriously.
Those WITH kids, especially with more than 1 or 2, could be viewed as the "selfish ones" in this light. Just a few more kids REALLY puts demand pressure on housing, living costs, and etc. in any community. "Thanks," for that...
Oh yeah, I started out that even though your post was somewhat offensive to me I hope my reply isn't received likewise because it's not intended that way. That said...
From experience I can tell you that 80 hours a week at the job will eventually take it's toll on you. Your business though.
I have tried to be extremely careful about people's choices here. People should have the right to not have kids, without explaining themselves. However, you shouldn't put us down that do and say things like I didn't miss out on anything when you don't know if you did or not. A simple, "I chose not to have children and I'm happy with my choice" ought to suffice, wouldn't you think?
Lastly, and this may make you angry but... You are not responsible for our children. We send them to you to learn. If their raising isn't completed yet, we will deal with it or life will set them straight but that is not what we are paying you for. If they can't behave by college they should not even be in your classes which are designed for adults IMO.
No industrialized country has a birth rate over 2.1. The countries with the highest birth rates, most of them in Africa, also have high mortality rates. Your overpopulation theories are crap.
I think the "population explosion" theory for not having children is bunk. Western civilization is barely replacing itself.