Why We Should Be Skeptical of Quantum Computing

It is widely believed that quantum computing is on the threshold of practicality, with performance that will soon surpass that of classical computing. On the contrary, it is argued that both the present and the future of quantum computing may be highly uncertain, for the following reasons:
1) The promised performance depends on entanglement-based scaling to massive parallelism, which has not been verified, and may be tested [1].
2) Even if the theory were correct, exponential sensitivity to noise for highly entangled states could make the technology impractical [2].
3) Evidence for entanglement in superconducting qubits can be explained using the nonlinear properties of classical Josephson junctions [3].
4) Evidence for entanglement in arrays of coupled qubits can be explained using conventional energy-band theory with delocalized states.
[1] A.M. Kadin and S.B. Kaplan, “Proposed experiments to test the foundations of quantum computing”, 2016, http://vixra.org/abs/1607.0105.
[2] G. Kilai, “The Quantum Computer Puzzle ,” 2016, https://arxiv.org/pdf/1605.00992.pdf
[3] J. Blackburn, et al., “Survey of Classical and Quantum Interpretations of experiments on Josephson junctions at very low temperatures”, Phys. Rep. 611, 2016. https://arxiv.org/pdf/1602.05316.pdf