If it's so expensive and durable, where does that bag go after school? Why does each generation have to buy new bags, why are they not passed down from parents to children?
Do you expect a sensible “because of reason X” answer to those questions?
I have zero expectation of rationality from this type of thing. People will give reasons to buy a new one, just like you gave reasons to use an old one. But ultimately it is the cost/benefit of aligning behaviors with other people which will drive their decisions.
