"Scientists have predicted that it may not be long before [the transistors'] performance is compromised by unpredictable quantum effects"
It is comforting to hear that the unpredictable quantum effects were, in fact, unpredictable. Science wins even when it fails.
Honesty, its not conductivity that's the problem. What we really need are transistors that have a big enough difference in conductance between their on and off states.
Also the thermal issues are relevant. It is a common misconception that quantum effects are the limiting factor in Moore's law.
It's disappointing you have to pay to see the original Science paper.