many serve videos on youtube use Sharapova as counterexamples. Granted her serve is not great and can be better, the IMG academy had tons of good serve coaches, why didn't they coach her to have a perfect serve? The question is not specifically about Sharapova. Many top pros are critiqued to have technical issues or peculiarities in some sort, why were the issues not addressed at an early age? considering the pros most likely had lots of good resource.