That's a fair question. I'd say roughly half. Which doesn't change the fact that a congested schedule reduces training/fitness opportunities, or that kids get just as hurt in non-competitive matches as competitive ones.
Also, while "my kid's" H.S. matches were only occasionally competitive, what about those kids whose H.S. matches are virtually ALWAYS a dogfight? Or whose teams included 18-20 players?
I'm not for a drastic overhaul. How about 2 full scrimmages (essentially non-counting matches), 24 regular-season and max-five state tournament matches? That would imply 26-31 matches, which is more than enough.
In Club/Academy, I'd favor a similar nominal trim.
If by doing this, you reduce the likelihood of a 16-year-old playing 70-80 matches, I'd say you've done something good.