I actually did start before the rotary revolution, self taught with nothing much more than black and white block diagrams from the days when our town library was a Carnegie Library! I was a senior in high school in 1978 and decided I wanted to make myself a quilt to take to college.
Strip piecing and cutting techniques came along with the rotary cutter. I personally learned a lot from Trudie Hughes books in the early days. Checked in on her website writing up this post, you go Trudie, and thanks for all the lessons.
In my own quilting, I've said it before that the book
Scrap Quilts by Judy Martin in 1985 forever changed my quilting career.
http://www.judymartin.com/meet-judy.cfm
The way we put things together has evolved since then, but it was the first time I had ever seen "scrap" quilts that I liked. I had only seen what I considered ugly use quilts and my brain lit up on the idea of using 6-10-100 blue fabrics instead of just one!
I think the rise of That Patchwork Place as a book publisher is also important. They showed that there was quite the market and with their books the standards for books was raised. Maybe I'm biased being here in the Seattle area and was able to tour the offices and raid the book sale room more than once.
Speaking of print, Quilter's Newsletter Magazine also raised the standard by becoming the standard.
https://whileshenaps.com/2016/07/qui...tbacks-fw.html
Edit: Safety pin basting, that was huge too.
Edit 2: Historically, machine quilting was being done as soon as there were sewing machines. It is entirely possible to have a civil war era quilt made and quilted entirely by machine. But machine quilting as an art form... yes, that I would agree more in your time line. The advent of the both the professional and the home long arm is definitely a change.