isn't 'real friendship' a case of no true scotsman? you see friendship as a together no matter what link.
An alternative view: a friendship is a relationship where you help each other grow as people socially and emotionally. A mutual effort.
Having kids in the western world is a choice not something that happens to you out of your control. I take some issue in the way you describe your "friendship" as it seemed to revolve around your needs imo. It's fine if your friends were fine with that, but they shouldn't be described as "bad friends" just because they chose not to bend their limited time around a situation that you fully chose to be in. Not wanting to be around kids does not make it a "not real friendship". You just have incompatible values and there is nothing wrong with that.
If you choose to make yourself less available by having kids, aren't you the not 'real' friend based on your view? They gave up some of their limited youthhood time away from activities suitable for them just to get stuck in a basement. For you. You got all the benefits of raising a kid plus having friends bending to your schedule. But you didn't seem to have returned the gesture. And if you did, you didn't mention it.
Imagine if one of your friends was working crazy hard on becoming a popular musician, paid tons of money to enter a 10 year education program path and was practising all the time, and either they don't come to your social events, if they do they come with their instrument and make you listen to it or you have to come to their recitals to be able to interact with them. They could argue that you are a bad friend for choosing to see them very little or not all, but you could argue back that they made a decision to invest most of their time into something other than your friendship and their time investments are a reflection of their value rankings.
It's not too dissimilar to single parents in the dating market complaining of people going away when the find out they got a kid or people interested in dating but not in playing a parental role.
You put a price on the friendship when you chose to make yourself less available, you can't complain when people leave you if they wish to be with someone who values their friendship more than you do (ie investing more of their limited time in seeing you in ways that don't revolve around your needs solely).