Not so.
The pocket protector seems to be making a comeback.
They are always made of white plastic. In the 1960’s most of them had company logos advertising STP or Texaco motor oil.
I never used a pocket protector but then I was more persnickety than most.
Many of my co-workers wore them proudly bragging how many shirts were saved from leaky pens.
I preferred a silver A.T. Cross pen and pencil in my shirt pocket without a pocket protector sheath.
The new pocket protectors are worn by tech people who have started a “geek chick” movement.
In case you want to make your own, DIY instructions can be found here. An old pocket protector patent drawing can be found here.