We only had scissors to cut fabric with?
I've sewed mostly clothing, and I still use scissors for that. I bought my first rotary cutter a few years ago, when I started quilting.
Sewing machines only sewed straight lines?
Most of mine only sew in straight lines. When I was a kid, as we got "good enough" my Mom let us use the fancy zigzag machine. All 11 of us learned to sew on a Singer 201.
Electric irons were only "dry"
Now I'd pay a lot to get a really nice dry iron. Burned out the new one, so I'm back to using a vintage one.
We "made" starch at home
My mom rarely starched anything - the cows and crops would not have have been impressed. I never learned out to use starch, and still rarely do.
Cotton, wool, silk, and linen were the only fibers available for fabric? (also jute for burlap)
Nope - but I do remember when leisure suits were in style, and double-knit was the "in" fabric.
Fabrics and thread came with a "boilfast" label?
Got lots and lots of vintage spools with that one them.
Pieces were cut out one at a time - templates were not made of plastic - cardboard, metal, paper
I don't remember using templates - I remember using the ruler to draw lines on the fabric and then cutting - and then sewing pieces together one at a time - no strip sewing and then cutting. Sure like the "newer" ways better!