Yeah its night and day. Friend of mine son plays JC and he's 19 and he looks like a man now compared to when he was 17 or 18 in hs. Not even the same kid. He joked it wouldn't even be fair if he was still in HS. I totally agree with you.
I also agree. But didn't someone confirm that Ryder Lyons is 17, not 19, and will graduate at 18?
Much ado about nothing, at least with regard to him.
I'll also add that while I agree with your example above, that isolated sample size doesn't apply to all kids. Many of them are monsters at 16 or 17 that others don't reach, if at all, until 19 or 20 (think D.J. Williams, among many others). People physically mature at different rates.
Hell, it's been well chronicled that Dennis Rodman was 5'9 at graduation then grew to 6'7 two years after HS. And the opposite often happens where a kid looks like a grown man at 13, 14, 15 then doesn't develop much after that. I've actually witnessed numerous cases of the latter throughout my own life experience.
Point is, many experience the transformation your friend's son experienced at younger ages. Some experience it even later.
There is no one size fits all here.
The above having been said, I believe most of us agree that 19 year olds in the Fall of their Senior seasons shouldn't be participating. And per the past and current rules, it sure sounds like it isn't a possibility.