This is a brief review of the experimental and theoretical quantum computing. The hopes for eventually building a useful quantum computer rely entirely on the so-called "threshold theorem". In turn, this theorem is based on a number of assumptions, treated as axioms, i.e. as being satisfied exactly. Since in reality this is not possible, the prospects of scalable quantum computing will remain uncertain until the required precision, with which these assumptions should be approached, is established. Some related sociological aspects are also discussed.I do think that QC is a failed research program.
QC starts with the hypothesis that it is impossible to efficiently simulate a quantum system with a classical (Turing) computer. I suspect that is correct. But the leap to scalable QC seems extremely doubtful to me.