Modern Grandparents and their involvement compared to the past (theory)

As many have regularly come across social media posts about grandparents and their lack of involvement today, so have I. This obviously doesn't apply to all families, but a substantial number could experience this.

With that said, I had a sort of epiphany theory a few weeks ago I have not come across elsewhere:

Today's grandparents are experiencing longer durations of empty nesting from the point of their last child leaving to their first grandchild being born. It could be a few years, it could be ten. This results in grandparents establishing more free-from-family liberty that past generations did not resulting in more self-interest and less family involvement.

Would you agree? Add to this? Counter the consideration? Certainly this could be polished or condensed, too.

First and foremost, it's not meant to relieve them of what might be considered responsibilities but it could explain part of what is being experienced.