It could have been a lot worse for you. Happily, it wasn't fatal.
As to cutting you up, I imagine that the windshield 'glass' was different at that time. Although you did say that you were launched through the windshield.
You get cut on the edges ~ modern glass breaks up in far smaller pieces ~ and I suspect it's not as hard.
Funniest thing is while they were stitching me up another guy was brought in who'd flown off his motorcycle ~ he had similar wounds.
The docs let him lie there on a gurney near my own listening to me moan and groan with every stitch.
Months later I discovered he was a guy I'd gone to highschool with and he and I lived in the same dormitory. He was upset that the docs let him hear me groan ~ said that was torture.
He never again rode without a helmet and full leathers and heavy boots.