College students form a major market segment of the backpack consumers. When I say college student, it can sometimes be applicable to high school though. I remember that in the past (when I was still attending school), my backpack would be filled with all the textbooks and some of them can be really heavy. But recently, with the emergence of moible computers with iPad and notebooks as the major driving forces, there has been a paradigm shift when it comes to classroom teaching. One of the shift is obviously towards e-textbooks instead of hard printed books. Theoretically, this should be a relieve to students as it would mean that there will be less books to bring to school which can only mean lighter backpacks. In reality, it is not as good as it sounds. Today's laptops are more powerful than the most powerful desktop of yesteryear and 17-inch laptop is common nowadays. How everyone wish that all laptops would be as thin and as light as the Macbook Air but its price is still beyond the reach of many college students.
Outdoor enthusiasts form one major market segment of the overall backpack market. Outdoor is a generic term and it encompasses activities ranging from camping to light hiking to professional mountaineering. I know the first name that will flash to most people's mind when talking about backpack would be North Face. It is no doubt a good brand but it is better reputed as fine college backpack maker rather than outdoor. In this context, Tetron is the brand that most outdoor enthusiasts would be looking out for. But it is important to set your expectation right though as the best outdoor backpacks, say the best backpack for hiking, may not be one that is most visually appealing.
In summary, I firmly believe that extinction is not something that is applicable when it comes to backpack. Backpack will constantly evolve and keep pace with the changing lifestyle needs and fashion vogues. The more relevant question would be what size would future backpacks take on. It is a question that no one can quite predict the answer at this point of time as it will largely be determined by the size of future computing devices. With all the hype surrounding foldable screen technology, it is a matter of when (and not if) this technology will become a reality and when that happens, laptop sizes will definitely shrink to half or maybe less than their current sizes. Eventually, backpack designers would have to come up with a design that better fits these devices.