Of the three, QC is different in that it's not a solution looking for a problem. If we ever scale QC to the point where it can do meaningful work (the "if" is doing a lot of work there - per your point about hardware), then I don't see it fumbling like the other two have. We have immediate and pressing needs that we know how to solve with QC. The other two are very much research coming up with cool toys, and product fucking around so that they can find out what to use them for.