Like I said I work on proper aeroplanes, what's a turboprop!
What's a turboprop? A proper airplane.
But starter-generators are found on turbo
jet airplanes, too. A lot of them. Perhaps it's just that in 30 years of working on airplanes you've moved in such small circles that your experience has been rather narrow...as evidenced by the fact that you've never heard of a starter-generator.