The backpack has been a standard method of carrying things for decades. At some point a few decades ago, backpack makers started making packs specialized for "city" uses, focusing on students and the like as customers. And to be honest, they did a so-so job of it; I stuck with the mountaineering packs that I grew up with until only a few years ago, when my carrying needs had changed significantly. Now, seeing slowing sales, they're rethinking what people's needs are, and trying to build systems from scratch.
What's interesting is who they are using as their research markets: the three heaviest users they could find. Mountaineers, students, and the homeless in San Francisco.
This makes excellent sense: people who live out of their backpacks, for which their backpacks are life-and-death important, will have developed the best strategies for using them, have the clearest needs, and so on. And in parallel to that, there's something else important here: it starts from looking at the homeless as people with complex tastes, rather than as a lumpen mass.
For the first time in quite a while, I'm interested to see what next-gen backpacks will look like. Someone may actually come up with something novel and useful.