When watching a sort of behind the scenes look at LOTR, it went on about how peter jackson pitched the idea of a LOTR series to many production companies, he wanted to do it in 2 movies, and no one wanted to do it, so his final chance was to go to new line cinema's, and he was planning on saying he would do it in one movie, but before he had a chance to say anything, new line said, well there are three books, i only assume you will be making 3 movies. Peter just nodd'ed and said, yup.
I think it defintely was a make or break movie, and it definitely made it.