Touching, DE.
My first, at age 8, was a .243, out of one of Daddy's Rem 788s. He bought them because they were cheap, but they were (and still are) fine, accurate rifles.
The first rifle I owned was (is) a Rem 700 in 270. I spent a whole summer raking and hauling hay for that one, and my life savings up to that point (13) on a 3-9 Leupold. High cotton!
I think you're right, a lot of my generation (30 somethings) cut our teeth on 243s, but older and younger generations had other options (or lack thereof).
I can see myself buying a rifle for my son in a few years, but I doubt that many folks my parents age and almost none my grandparents age would have even thought about buying a whole nuther rifle for a child to shoot. Over consumers, we are.