system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why are textbooks so expensive in the United States and why hasn't this been remedied?

I'm studying at university in the United Kingdom and have friends in the US who complain a lot about the textbooks they have to buy and the cost of them. The costs seem absurd. 

I compare this against the UK where I haven't had to buy a single book for a three year course in Physics and Philosophy at a prestigious university. I'd estimate that 70% of my required reading for all my modules is available free online through my library membership and the other 30% can be borrowed from my library. 

Do americans not use libraries (I doubt this is the case) or are they not available? 

A few of my books say on them "For sale only in Europe, Africa, Australia and Asia" which leads me to believe that for some legal reason they can't be sold in North America. Why would this be the case?
gpt
Price discrimination by the publishers. They can sell higher in the US, so they do. A budget for textbooks is included in any US university's financial aid packages, student loans, etc. 

There is also an aspect of subsidy going on; textbooks can be sold internationally much more cheaply in part because they're being covered by the high revenue from the US.