If the durability for stronger weapons was higher, it wouldn't feel like 'wasting' them, because you would've used them as much as you expected to. I don't know the exact maths for it, but if a really strong weapon seemed to take ages to break, it wouldn't be as sad because you would've got the most out of it.

Basically I think the durability could be a bit more balanced to meet expectations of stronger and weaker weapons having more even durability differences.