Of course Netflix already abandoned the mail delivery model as their focus, they even tried to spin off that business, and it is only a small portion of their revenue today. There were a lot of factors that went into Netflix's success, including working closely with the USPS on rapid delivery, a terrific web presence, and catching the DVD market at a point when they were dropping in price but still a popular format for consumers. The window for Netflix was actually quite small (I suspect you are young and don't remember the time before DVDs) as DVDs were the most rapidly adopted media format in consumer electronic history, and are imploding at an impressive rate as well.