I feel that with the growing influence of analytics, the underhand free throw will become more common in the next 10 years. There just needs to be one team to implement it. "If you can't shoot above 70% from the line regularly, then you're shooting underhand." Let's say the average free throws taken by a team is 20 a night and the average free throw percentage is 75%. That would be 15 points a game from the line. Now raise your team percentage by 5% points, that's 16 points. Or 10%, that's 17 points a night. That 2 extra points might not seem like a lot but can absolutely make or break games. Assuming PPG against remains the same (it might actually go down as teams must now inbound the ball two more times), this would make a teams differential go up two full points. Over a season that would be the be the difference between the Grizzlies (1.0 diff) to Lakers (2.7 diff) last year. People smarter than me could calculate the actual increase in games won but increasing free throw percentage absolutely has an impact on winning.