I think the nice thing about breeder reactors isn't so much that they produce additional energy or are economically profitable on their own, but that they have the potential to eliminate nuclear waste that has accumulated in the last few decades, therefore effectively eliminating the storage problem.
Consider this: Storing nuclear waste costs something. A country might pay $1bn to store its nuclear waste for a hundred years. Instead, it could give that money to breeder reactors so they get rid of the nuclear waste permanently.
Breeder reactors don't have to be profitable only by producing electricity. They have another selling-point, and that is that they eliminate the nuclear waste for good. That's also worth something, and politics might be willing to pay for it at some point.