They just sound like crap friends tbh. Anyone with two brain cells to rub together and a teaspoon of empathy would realise that talking almost exclusively about your kids to a friend without kids who has struggled with infertility is going to be hurtful and/or boring as heck.
I haven't personally found this to happen with friends of mine, no. When I was pre-kids and they had kids we talked about the kids because I loved them and they were so important to my friends but we also talked about plenty of other things: our careers, hobbies, relationships, interests, trips, money, education, TV, people we knew, so many things.
Since I've had a child I'm very aware of not being a bore about him and save the bulk of my chat about him for my parent group friends unless asked, and then I'll talk about him a bit but then move onto other things depending on what our usual topics of connection are (some friends I bond with over our professions, some over specific music, some over other things).
The 'haha how do you have so much free time' thing is incredibly insensitive when I'm assuming that being infertile you've actually wanted to be busy with a child and would give anything to have that experience. It's also patronising. And incorrect. I have a child and he's asleep for 630pm every night so I have hours and hours of free time each week without him to see friends, partake in hobbies, spend time with DH or relax on my own. Before I had kids I had periods of my life being WAY too busy! Working eighty hour weeks, balancing full time studying with several jobs at once, just absolutely manic at times. I have a much more relaxed life with lots more free time now than I did pre child.
It's a common belief that friendships will last forever or that if it's lasted long enough it'll keep going, but that just isn't always the case. I lost a best friend of two decades a couple of years ago. It happens. Ask yourself whether the friendship is meeting your needs or serving you at all as it is now rather than hanging onto the past. A good way to avoid holding onto friendships that have passed their best years is to always be open to meeting new friends. You're not just inevitably stuck with these women if you want close friends. There are potential new friends everywhere.
I'd let these go quietly, contact them less, maybe meet up if they ask but don't make any particular effort. I don't think your experience is uncommon or unique or unusual, but I do think it's down to them being crappy friends that sound devoid of anything interesting about them or any social skills/emotional intelligence.
It's cheesy but I like this phrase: some friends are for a reason, some for a season, some for a lifetime.
Cherish the happy times you had, recognise that relationships are always in flux, keep an open heart to new friends and let these ones fall into your past. I'm sorry they're like this.