For this theory to hold up you would need to explain what changed as high schools in the US have loved sports since at least the 40s
I hate to break it to you, but a lot of our most valuable research is produced by people who did their primary education outside the US. Just go to a STEM research lab at any US university connected to a Nobel prize or Fields medal in the last 10-20 years, and it will be almost completely made up of internationally educated students / professors / etc.
Like a sorting algorithm which is O(n) on nearly-sorted input - the utility is limited.