Waste is energy that just needs to be alleviated productively in a different mechanism than the one that produces it. It's an opportunity not a liability.
My point is that it is presently an opportunity we are not capable of exploiting. Our technology is not advanced enough to exploit it. Breeder reactor technology has proven too difficult, expensive and dangerous. See the failed Monju project, for example. Perhaps in the future, as people learn more, they may be able to make effective breeder reactors.
My guess is that something much better than fission will emerge (such as cold fusion!). Breeder reactors will never be needed, so the spent fuel will be removed from earth.
I would not call this an opportunity so much as a latent potential. Or a dormant potential. For all of history, silicon had the potential to produce rapid computation, but we did not learn to tap that potential until 1954. It was dormant for all of human history. Anyone can see that breeder reactor technology is possible, but it may remain dormant forever. Countless technologies, large and small, have been imagined, explored to some extent, but never developed into practical machines. Many never will be.