A Brief History of the Lawn Chair
valetmag.com
valetmag.com
People buying lawn chairs in the 1950's were probably old enough to remember aluminium and plastic as having been luxury goods in their childhoods.
[1] on the US side: https://en.wikipedia.org/wiki/Defense_Production_Act_of_1950...
[2] in the USSR, I've heard they wound up even making hula hoops out of the stuff. Ever more paper clips, comrades!
Perhaps, but aluminum chairs seem like a no-brainer anyway. The basic properties of aluminum considered strictly as a material are (1) it's easy to lift; and (2) it doesn't rust. Both of those are obviously what you want in a portable chair.
The folding chairs that I'm familiar with seem to be mainly iron, and definitely do rust.