i really dont know why the US produces specialists so well, but as an american homer i think it has to do with some sort of national mentality.
in my opinion, what ive noticed in the US is that specialists primarily come from hobbyists, resources and a strong market.
for hobbyists, most of those guys whose pictures are listed above were building computers in their garages/dorm rooms. the dorm im staying at Univ. of Texas is the same one Dell was originally building and selling his computers out of. alot of my friends who are engineers werent pressured to do so. they just have this innate sense of wanting to know how things work...mostly taking apart gizmos and the like.
engineering students i know from korea (im picking on korea because my best friend is from there and is in chemical engineering) are leaps and bounds ahead of american ones regarding math and theorems, but it seems like they lack that innate sense of curiosity. theyre buried in books, are incredibly academically disciplined, but arent out having fun building cool stuff. for example, an electrical engineering buddy of mine built a beer pong table that lights up different colors according to how much pressure is applied to the table, so the table changes colors depending on the amount of beer in cups.
programs in the US are very selective and compe ive, but theres so many different programs that people tend to jump around until finding the right one. the US offers so much in that regard. just about every tier 1 university has the resources/program to fit a specific student's interest. also, donors like to have donating wars to see who can donate the most money to have programs and buildings named after them. right now at UT, bill gates and dell are donating millions to the computer engineering and programming programs. so allowing the private sector to have a bit of influence is positive in that respect.
also, companies dedicate alot of resources to job training in the US, and many people can be in job training for up to five years before theyre given the reigns on their job description. the (relatively) strong market allows companies to do this. theres also a strong flow of information between jobs and job prospects. many people choose to specialize in a field simply because its in high demand.
i could go on and on, but ive typed way too much, and im getting pretty biased

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