Over the last 40 years I've heard of isolated occasions when Age Integration was successfully practiced. I thought I should post a recent example I found here to get people thinking outside the box! I have read of a similar example in my province, British Columbia, so this is not a one-of!
What's particularly great about this approach, is that it helps college students subsidize their housing needs in a positive, healthy way.
My 40 year old example was of an elementary school and a seniors day care being in the same building. A lot of the children rarely saw their biological grandparents, so they adopted new ones! There was never a shortage of volunteers for children to read aloud to.
Christopher Alexander covers this concept in his book, A Pattern Language.
https://permies.com/t/110164/Pattern-Language-Christopher-Alexander
He recommends ways to keep well elderly active and visible in the community. I suspect he'd be appalled at the "over 50" gated communities which seem to exist in my area. I guess it's a bit like growing a monoculture? Polycultures are more interesting and fun!