In the late 60's and early seventies, especially pre '75 we'd get a few families from door to door, (Mum, Dad, Kids - not middle class though) some that are still around now as grandparents, kids and grandchildren - attending meetings and become the elders from the first or second born-in generation.
But they are now dying and going into care homes (the original parents) and some of their kids in their 40's and 50's are a lot less committed (lots of hols and absenteeism). The grandchildren below age 30 just hang on in there for social reasons or have become absent.
But the last family that came in from the door to door work would be in the 80's. Since then it's been oddball singles and vulnerable single mothers.
Give it 3 years and I reckon our three eldest elders (late 70's) from this era and their wives will be "spare wheels" as in useless to run any KH stuff, in and out of hospital, in care homes or dead.
The last middle class types seem to be the now elderly sons of women who came in from door to door in the 1940's and 50's who were supported financially by their non jw middle class husbands.