My grandparents started in their 60's and supported themselves quite comfortably thru retirement.

Rich, you're going to have to go back to school to be able to keep up :D Congrats to your grand kids and their proud grandparents!

If they can spread the cost out over 2 families and/or grandparents, all the better.Our house is pretty big (4/3 2700sqft) and we get multiple families at a time.

My grandparents had  multiple rentals and got them paid for.

In 1900 my immigrant grandparents bought a house in a Chicago slum.

I remember back in the 1970's when I was a little kid coming down to visit grandparents and uncles and all this area was just pasture land. 

Both my grandparents were teachers and they lived in a part of L.A that is now an exclusive area , homes now sell for $2-3 million and up.My grandma sold at the worst time , during the crash .. but that’s another story .

For me personally, finances aside, I would have a different opinion of purchasing my grandparent's lifetime home than I would one of the shacks we lived in for a year or two when I was a kid. 

Looking at current demographic in CA, many cities in this state are actually being saved from further 'disintegration' is because their parent or grandparents bought properties that they can use.

So the elderly grand parent finds out the kids have little time for them now.Money is great, business success and all of that but you have to be present in the moment and enjoy today.