Your assumption is correct, and your cautiousness is warranted. I do expect the polynomial complexity to become better with future improvements in algorithms. Either way, it is on us fanboys to make devices that fulfill these claims.
Best of luck. having my skepticism disproved by the QC folks woudl be a major win, but it's not something I'd spend my time on. I think it makes more sense to improve existing codes to run as fast as possible on the biggest supercomputers we have, although even that isn't super useful because, as far as I can tell, better chemical simulations don't lead to better applied science in the field of chemistry.
