Hmm, I thought quantum computing is not happening. See https://scottlocklin.wordpress.com/2019/01/15/quantum-comput... Can somebody dispute this claim?
As an experimentalist, I would agree with the sentiment that the potential future applications of Quantum computing probably receive too much media attention, given the maturity level of existing technology.
The technical arguments as to why building a useful QC will be impossible are a bit more shaky.
First, the post seems to imply that the calibration effort scales with the number of gates in the algorithm. This is false. In reality, the number of interactions that need individual calibration is basically the number of qubit-qubit pairs exposed by the gate library. The most mainstream approach to error-corrected QC only uses nearest-neighbor interactions, and hence the scaling is linear.
Second, it is not clear to me why the number of computational basis states (2^N) is relevant to the engineering at all. Following this line of thinking, the recent Quantum supremacy result by Google already amounted to a mastery of 2^53 ~ 10^16 degrees of freedom.
Third, an argument is made that large-scale error correction will not work because of correlated errors, of unspecified nature. I think a claim like this should come with a mention of at least one concrete source of such errors, so that we could estimate its magnitude and potential severity. Note that such calculations are almost the essence of day-to-day work of a physicist.
In the absence of more detail, I can make a generic counterargument: Any phenomenon causing such correlated errors by definition affects multiple physical qubits at once, and will tend to be more macroscopic in nature. This is in contrast with the processes that limit the fidelity of one- and two-qubit operations, which is what the error-correcting code will take care of. Macroscopic disturbances are exactly the ones that we can attempt to shield against with clever engineering.