Ouch. There is a huge degree of truth in that. Situations differ however and I know of at least a few local book exchanges that are making a living (i.e. in operation 2+ years).

I do however not know of one central/large one. There are several reasons why in some cases it succeeds and in others not. In poorer regions/countries people would look for more ways to save money (the pressure isn't really on an Ivy League guy to buy a $50 book instead of a $100 one when his tuition is $40,000. In countries where students live on less than $3000 a year it is).

A solid business idea I have seen is a chinese copy center - you hand in a book and the next day get your book and copy for about $20 (this business is in operation more than 7 years without any uhm... legal problems).