This was all centered around a particularly eccentric knitting fad circa 1950.
The book did not at any time explain why you should knit something for the top of the TV or radio. It begins with the assumption that you want to, and that it definitely needs one.
The point is that by 1950 regardless of the state of pop culture everywhere, some grandmotherly women liked to knit. It's a collision of cultures, knitting and new media. Were this book released today it surely would include patterns for knitting Ipod caddies, or laptop doiliies. Change is more difficult for some people than others.
Radio scarves should of course not be confused with the (S.C.A.R.F.) Sunday Creek Amateur Radio Federation based near Hocking College in Glouster, OH. http://www.seorf.ohiou.edu/~xx016/hide/clubs/scarf.html