60th. Birthday party

My brother-in-law turned 60 during the week, and his sister, Mrs. Lear, hosted his party last night.
Lots of old friends and family ploughed through champagne, wine, digestifs, salmon, panacotta etc etc, and I did the washing up. I did, contrary to my usual rule in UK, toast the birthday boy with a mini-glass of bubbly.
What it did make me think about was the way connections remain. Some of the people had not been seen by the BiL for more than 30 years, but they still turned up and enjoyed the reunion. This being the West of Scotland, my generation are still pretty much all here - as are the generation before and the one before that. Many years ago when Mrs. Lear and I might have gone to live abroad, one of the thoughts we used to iterate frequently was that anyone we knew would still be here if we ever came back. In the event we stayed here - and yes the others are still all here.
My children's generation, however, are much more likely to have moved away.
Two of the three Ms. Lears are in London, having been in France and America, and the Middle East, whilst their friends from when they were little are also largely removed elsewhere.
Its a phenomenon that has probably been around in England for a long time, but here it's quite new, and has resulted in a generation of people either already grandparents or approaching that state who are wondering if they should move to be nearer the children.
I simply pose this as a question, not in any pejorative way, but why should they move? Should the children not have to deal with their own children, rather than having grannie exhausting herself three or four days a week looking after them? My generation had little or no help from the ancient Ps when the children were small. Why shouldn't my generation simply do their own thing and leave the children to get on with it?
Personally, I have every intention of not being a doting grandparent.
Mrs. Lear says I bored everyone to death about my own children, and she's sure I will do the same with any grandchildren.
And will insist on them being brought frequently to be looked after.