BankShot
The Kleuh Level
These type teams are usually all adept ball-handlers who have great court-awareness. Today's NE Dubois & Barr-Reeve's squads in S. Indiana are good examples. You're correct re: general FT shooting (HS/College), but HS's that can use this style of play successfully are the EXCEPTION rather than the RULE. It actually presents a MENTAL CHALLENGE to the opposing coach & players, who are generally NOT programmed for this. It's an extremely frustrating experience, to have a 1-1 advantage @ virtually every position on the court, and have this flushed down the toilet and forced to play this way. But, it's BASKETBAll. Just not what we commonly see.75%+ free throw shooting would be top-50 in NCAA D1. It would be one of the top-25 teams in the NBA.
I only go to maybe one Indiana high school basketball game every 5 years. I live in Texas, but I may see a local game when I go back home. If you say they’re shooting 75%+ then so be it, I’ll believe you. Statistically, though, that seems relatively impossible.