So what if the movie is true to the books or the original movie. If an ending is unrealistic, it is unrealistic no matter it is true to the book or not. Maybe it's just a bad idea to bring a 100+ year old "science fiction" to today's theater without rewrite the script a bit. I mean virus or bacteria may seem mysterious and uncurable back then, but today we have many ways to deal with it. If we travel to some third world country, we are advised to take precaution, mayb take some shots or whatever. It's just hard for today's audience to accept alien supposed to be much advanced then us don't know about preparing themself against possible virus/bacteris/pollution in the new environment, or have no clue how to cure those things.