It's supprising that this is turning into a debate. If the manufactorer is not to blame replacement should be handled by the consumer. It's rediculous to ask for anything else. The manufactorer is not, and shouldn't consider itself responsible for consumer actions; this is not bad customer service! If you think they should cover replacement under this example you're just trying to get a new rod for much less or free. If you think they should replace the rod for the materials cost alone you're just trying to pay less. You wouldn't ask a boat manufactorer to replace your drift boat if you total it on the river--insurance aside; and, hopefully, you wouldn't ask them to replace your boat for the cost of materials alone. Don't ask businesses to assume responsibility for you.
Replacement generally is handled by the consumer when the consumer is at fault. But if a manufacturer can offer a replacement for a reasonable cost and make a profit they should. (not "something for nothing")
Marketing is about developing a relationship with the end user. If you and I make comparable products at a comparable price, yet I take better care of the end user, I'll likely be more successful. Your margins may be higher, but I'll slowly gain the customers that feel they were burned by you.
There is no legal or moral grounds to justify a company be obligated to replace a product the consumer is at fault for damaging, but there are business reasons to do so.
Comparing consumer goods to items like automobiles and boats is not apples to apples. Cars and the like already have instruments in place that take care of this issue such as initial warranty, extended warranty, comprehensive and collision insurance, gap insurance, and scheduled routine maintenance.