We spend a large part of our educational budget on non-instructional items such as security, which other countries don't.  That's why we spend more per student than most other countries.  


Also, I'd say we've made quite a few advancements in technology.  These things take time.  The internet took many years to develop and come into it's own.  Before long we could put a man on Mars.  The development of robotic limbs has come a long way too, which will help amputees and paralyzed patients.  And they'll be able to control these limbs with just their minds.  A lot of developments have been in improving on technologies we already have.  3D Printing has really come a long ways.  

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