"I'd say top 10 Prep and top 10 T1EHL would be pretty close games." You are crazy. A top U-16 T1EHL team would smoke almost every prep team and give the top few a game....and that includes their 19 year old repeaters.
So how is it a handful of prep kids end-up in the USHL and about a third of every T1 team ends up there?
Prep hockey isn't all that.