It doesn't matter whether you can or cannot achieve high temperature superconductivity or fuel cells, they will always be on the list because if you could achieve them they would be extremely valuable.
“When I started working, I didn't have a clue what I was doing, in that I was just wandering around, hoping that I could succeed. Then after I got a little under my belt, it took me about 25 years to feel like I knew what I was doing.”