Purely athletic reasons? No. I think that is a bit off. I hear what you are saying. The stereotypical asian/indian parent drives their kid excessively with academic focus to the detriment of other aspects of life and personal development. Conversely there is a subset of culture in the US where parents only focus on the athletics. That's pretty weird also. As a just OK former HS athlete, I take a lot of pleasure in watching my kids athletic exploits but I'm more proud of their academics. Fortunately for me, my wife and her side of the family are incredible athletes including NCAA champ/US nat team/NFL. I married up for sure. But we wouldn't have done it just to get some sort of an advantage in sports.
When 2023 was age 5, he was too smart to hold back from kindergarten. During elementary school, he always scored 96-99th% on annual standardized tests but something was off. He struggled socially and wouldn't quite do as well as you would think he should; mostly because of things like not turning in assignments or being sloppy with work. So we repeated 6th grade to allow him to mature. He just happened to physically mature also. I think there is some pretty good data that suggests boys often benefit from a delay in entering school when reasonable. Like I said, summer birthdays like my kids might make sense to me.
Athletically, 2023 was 5ft9 140lbs at age 16. He gained 25lbs by age 17 and earned all sorts of awards as a junior. If we held him on the same track, maybe he wouldn't have earned those same accolades until his senior year? Does he have the same college baseball opportunities then? I suspect not. As it stands, I think he did better in school with our decision (leading to more merit money) and better in sports (leading to athletic money and a good fit college).
I get what people are saying about draft age and what P5 schools are looking for. While I think my kid will be a good college player, he's probably not ever getting drafted or ever going to go into a portal to try and move up.