Man---I know every damn thing in that video. I went from age 7 to age 16 in the fifties (and started climbing at age 14). My wife was once in the Peanut Gallery on the Howdy Doody show (the video has a shot of the clown Clarabelle squirting Buffalo Bill with a seltzer bottle.)
I think the different hole sizes in records were at least partially an attempt by RCA to produce something incompatible with Columbia, which had introduced 33 1/3's with a small hole. (The earlier 78's also had the small hole.) But the compatibility issue was pretty easily solved with a press-in hole adapter, two of which are shown in a frame of the video.
The 45's were meant to be stacked, as many as 10 high, on a fat spindle, and would drop down sequentially and be played. The small hole in the Columbia records was more sensitive to deformation when those records dropped down a thin spindle.
My wife and I have two shelves of 33 1/3 vinyl and a turntable to play 'em on. My daughter, who is now a professional musician, grew up with that stuff and knows it pretty well. So maybe, just maybe, we didn't totally screw up the parenting.
Being born in the I.G.Y. means I was more a child of the sixties. I can recall convincing Mom, when I was four or five years old, to buy me the record "Meet the Beatles". She said she didn't like their long hair but she bought me the LP anyways. "A Day in the Life" was just on the horizon. However, I did grow up immersed in the fable that science and technology were going to fix our lives, which I suppose was a sort of a remnant from the fifties.