For a lot of technology, most really, the best way to study how to improve it is to make the best thing you know how to and then work on trying to make it better. That's what's been done with all the current quantum computing attempts. Pretty much all of the industry labs with general purpose quantum computers can in fact run programs on them, they just haven't reached the point where they're running programs that are useful beyond proving out and testing the system.
So it remains for you to show that AI.ε ~= QC.ε since JvN proved the case for a system made of similar parts, that is vacuum tubes, with the same error probability.
(p.s. thanks for the link)
Has he remarked on it and my search-fu failed?
Quantum computing may or may not get industrial results in the next N years, but those folks do theory, they often if not usually (in)validate it by experiment: it’s science.
It is also completely undefined in the theory: the theory doesn't say anything at all about what interaction constitutes "a quantum interaction", that keeps you in the deterministic time evolution regime; and what interactions constitute "a measurement" and collapse the wave function.
So, this is a major gap in the core of quantum mechanics. Quantum computers are all about keeping the qubits in the deterministic evolution state while running the program, and performing a measurement only at the end to get a classical result out of it (and then repeating that measurement a bunch of times, because this is a statistical computation). So, the hope is that they might shed some light on how to presicsely separate quantum interactions from measurements.