Skeptically Hyping About Quantum.  Some say never, some say 5 decades (U.S. Military), some say 5 to 10 years (IBM).  But nobody is saying it is not coming.  Because Quantum is Coming.  Quantum will get here sooner if it could be capitalized upon; as is the silicon chip.  Qubit. 

Excerpts from… Quantum Hype and Quantum Skepticism. 

  • …The popular media regularly reports breathlessly on quantum computing: “Quantum computing will break your encryption in a few years”; “Why quantum’s computing time is now”; and “The computer that could rule the world.” Yet the physical realization of quantum computing has been a hard slog. A Canadian company, D-Wave Systems, has claimed to be the world’s first company to sell computers that exploit quantum effects in their operation. But the D-Wave machine is far from being a general quantum computer, and several researchers disagree with D-Wave’s claims.
  • …several quantum-computing researchers have expressed skepticism regarding the physical realizability of the quantum-computing dream. Quantum skeptics agree that quantum computation does offer an exponential advantage of classical computation in theory, but they argue it is not physically possible to build scalable quantum computers. Gil Kalai is one of the most prominent quantum skeptics. All physical systems are noisy, he argues, and qubits kept in highly sensitive superpositions will inevitably be corrupted by any interaction with the outside world. In contrast, quantum-skepticism skeptics, such as Scott Aaronson, view the realizability of quantum computing as an outstanding question in physics,c and regard the skeptical view as representing an implausible revolution in physics.
  • …An important part of the report is an analysis of why and how computing technology scaled exponentially in performance for over half a century. This scaling was mostly the result of a virtuous cycle, where products using the new technology allowed the industry to make more money, which it then used to create newer technology. For quantum computing to be similarly successful, it must create a virtuous cycle to fund the development of increasingly useful quantum computers. But the beauty of classical computing is that developing algorithms is incredibly easy. Every teenager writing a program is developing an algorithm. In contrast, in more than 25 years of intense research on quantum computing, only a few dozen algorithms have been developed. It is conceivable that governments will pour major investments into a small number of critical quantum-computing applications, but this will not give rise to the thriving marketplace that is needed to sustain the virtuous cycle. Count me a quantum skeptic!

Source:  Communications of the ACM.  Moshe Y. Vardi, Quantum Hype and Quantum Skepticism…