There's plenty of interest in treasuries without the Fed's action (indeed, despite it, since their goal is to lower interest rates).
LOL no there isn't , The fed buys more than half of all treasury issues. China is a net seller, US Households are net sellers, Mutual funds are net sellers, Banks do not buy treasuries.
Foreign treasury investment has been going downhill for the last 5 years.
The problem with spouting things you learned in college from a book is that often that book is out of date and is just plain WRONG.
http://www.ritholtz.com/blog/2011/08/who-is-buying-u-s-treasuries/