The textbooks you read in school are the same that are taoght in India and China..their secondary school has equal calculus (may be more)...by the time their students post-graduate, more than half of Americans have dropped out anyway. The time has already shifted. It is only the said infrastructure such as clean water, electricity., roads bridges etc..that people from brilliant talent from likes of India and China keeps flowing into America. And this taleny in return keeps your rovers landing on Mars...Saturn ..wherever now and in future.
So try this - give them a place no where to go but stay in their respective countries. I say America got most 20 years before being technologically ghosted.
I give America only 5 years in case they stop maintaining their infrastructure today.