Fortunately, though extrapolation is an element in science fiction, it isn't the name of the game by any means. It is far too rationalist and simplistic to satisfy the imaginative mind, whether the writer's or the reader's. Variables are the spice of life. This book is not extrapolative. If you like you can read it, and a lot of other science fiction, as a thought-experiment.
Prediction is the business of prophets, clairvoyants, and futurologists.
It is not the business of novelists. A novelist's business is lying. The weather bureau will tell you what next Tuesday will be like, and the Rand Corporation will tell you what the twenty-first century will be like. I don't recommend that you turn to the writers of fiction for such information. It's none of their business.