What happens when that broken NWC is fixed? The data was dumped long ago so nothing is lost when the cart dies. The original EPROM can be desoldered, reprogrammed, and then put back. Someone good at soldering can do that without anyone being able to tell.
Eventually all the NWCs, all protos, all repros, and almost all NES unlicensed games will be dead. How they are cared for makes little difference. Unless the carts are regularly dumped and verified nobody knows how many are already losing data.