headinhands - in our case, we made the decision to leave the UK (and therefore leave DH's parents who are in Ireland), to be closer to my Dad who had bowel cancer. My brother (only sibling) was also in London, so my and my family were moving back to be closer to him.
We felt slightly better about about moving so far away from DH's parents, because one of his brothers lives a 15-minute drive away, and they have children (PILs's grandchildren), and he has another brother in London.
My Dad had no children close by and no grandchildren, and was widowed and ill.
We made the decision to be close to him, and I'm thankful for that, as he died 4 years later. We got to live relatively close by for his last years.
People probably aren't answering your question because it can often be complex, with myriad different factors including decisions.
Basically - we tried to do the right thing (which I think we did), knowing we were never going to be able to please everyone.
Our decision hasn't impacted on our relationship with our siblings in the slightest.