There's a huge difference between expecting to pick up exactly where you left off immediately, and expecting to see your parents who now live just 20 minutes away for more than a brief visit every couple of months.
Well, my parents only live a half an hour away and I only see my mum once a month or so. I haven't seen my dad for about two years now. Different families have different ideas of normal. Seeing parents once a month is normal for many families - I don't think that, by itself, it's a sign of any issues.
Would you really not want to try and make more time for your own children and new grandchildren after they'd got back from living overseas, just because you'd got used to them not being around?
Well, it depends what else I had going on in my life? OP hasn't said, but many grandparents work full-time. They often have caring duties (either young children who still live at home, or elderly relatives). They have their hobbies and their own friends to see.
If I'd moved abroad and then came back after several years, I wouldn't expect my parents to change their lives and plans to accommodate me. I'd expect to see them when it suited all of us, whether that was weekly, fortnightly, monthly or even less than that.
People have described her as 'swanning off', 'abandoning' and 'hurting' her family, 'not giving a shit about family values' when she was making her own choices etc. I think it's pretty fucked up to think of your children as 'abandoning' you by moving abroad, actually.
I think people are trying to show the alternative viewpoint. If it was okay for OP to move abroad and not see her family for weeks/months on end, why isn't it equally okay for the parents to choose not to see her for weeks/months on end?