The Manhattan project was a simple if colossal effort in taking the isotope fractionation and purification process from the lab bench, where it already worked, and doing it on an industrial scale. There were also issues of assembling the fissionable mass and holding it together long enough for a trigger to set it off and get a meaningful yield. These were all technical challenges, but clearly acheivable.

The problem with room-temperature superconductors is that NOBODY knows any that work, or has ANY idea what might work, yet...

At this point, modest amounts of money are going into semiconductor research, largely through government labs and electronic companies. If it get's close to working, the auto manufacturers will climb on board. For now, their role is to make the autos that the market wants. The last few years in the USA that has been monster gas-guzzling SUV's. This may change...