[someone123]

I think of it in terms of character and uniqueness or quality of materials, not age. The aluminum solar screen would be an unusual and interesting feature today.

It's true that these old architectural features can seem ubiquitous during one era and become rarer in the next. A lot of 50's-80's stuff is torn down today without a second thought. Halifax has lost maybe half of its modernist 50's-era architecture in the past 15 years (Bank of Canada, Herald, Ralston). It quickly went from being somewhat common to being endangered.