[paxys]

This isn't really the math. A $50 backpack from a decent brand will easily last 5-10 years under normal use. You aren't getting anything extra in terms of durability from the $400+ worth of exotic materials and handcrafting. It's a signal of social status, like any other piece of luxury fashion, but not much more than that.

[JohnBooty]

What's "normal use"? Here was my "normal use" as a student in the 1980s and 1990s.

    - 4 or 5 large books at once, bag often fairly bulging
    - Zipped and unzipped probably > 20x daily
    - Dropped onto school, home, and schoolbus floors dozens of 
      times daily with various levels of care
    - Some walking, some weather exposure (less for me than 
      many others)
    - One strap always carrying 100% of the load because the style
      was to wear it over one shoulder; it was never acceptable
      to wear it with a strap over each shoulder as actually 
      designed

Anecdotally I didn't see a lot of $50 Jansports lasting multiple years under those conditions and even if they did they would be pretty grungy.

Now... today as a middle-aged adult? Yes, a $50 Jansport easily lasts me 10+ years, probably more like 30, basically a lifetime purchase.

Also... today as a student? I guess it's less physical books and more Chromebooks so sure yeah maybe $50 Jansports can be lifetime purchases for kids, why the hell not

[maxglute]

Maybe I'm talking out of my ass but this seems to be designed for regimented JP primary school life. Rigid central compartment for books. No need to accomodate for lunch boxes or water since you get that at school. Or you clothes/shoes for sports and after school activities.

[JohnBooty]

I think many kids carry a packed lunch (bento) but carry it separately in a box wrapped in a cloth or separate bag. I've not visited nor lived in Japan, I'm sure somebody can correct/expand.

https://en.wikipedia.org/wiki/Bento