1 and 3 are very important points. 2, Price competition likely was less important; in Austria (and I think, Germany) there exists the "Buchpreisbindung", the p

1 and 3 are very important points. 2, Price competition likely was less important; in Austria (and I think, Germany) there exists the "Buchpreisbindung", the price of books is mandated, no seller must offer a lower price; also, tax was always included, from day one. They still won big, very early, very fast. I remember that an employee of a (now defunct) bookstore told me "please order via Amazon, you'll get the book faster, and I cannot offer any added value".