I agree that throwing mechanics are important. But I hope you're not suggesting that sound mechanics would eliminate the need for pitch count limits and appropriate rest intervals. Even with the best mechanics, pitching is physically stressful at any level, and the evidence indicates that teenagers (who are still growing/not fully matured) are at greater risk even than the adults in the pros who suffer injuries despite having the very best coaching and conditioning. This is especially so in our current era, where players may be pitching from March through October, as opposed to back in my day, when maybe you went from March through July.
One thing I do believe is that we should be more concerned with overuse as a regular thing, as opposed to it happening only once in an entire season. To me, the rules could be more lax for state tourney week. I don't mind pushing a guy a bit beyond the norm just once, especially when he can then rest a few weeks before he might even pitch in a summer game. And sometimes we forget that for most, the state title game is the most important game they'll ever pitch in.