I looked up the omnigrid website, they didn't have much "about us" info, maybe I missed some other section.
I did find this wikipedia entry that says Olfa introduced the rotary cutter for sewing but did not target quilters in 1979. I think it took rulers for that!
https://en.wikipedia.org/wiki/Rotary_cutter
Quilter's Rule came out in 1983.
I think my first ruler was the Salem Rule, I couldn't find out any info on when it came out on-line but it says copyright 1989. That seems about right, it was after my son was born in 1988. Plus, I was using rulers full time before he was in Kindergarten.
Way before large squares or triangles came out, I bought a non-marked drafters triangle that was about 16" on the right angles.