What failed was not the QR code because it was not a poor choice of technology. It was designed in such a way that it was good for one person to order but not for six people to negotiate.
And that is how replacement technology operates. You study the activities of a human, and then you build automation around that. What you don't get is all the context the human is handling along the way. The social reading, the handling of exceptions, the time when someone passes on the cake and gets it out of the way.
Replacement technology doesn't inherit any of this contextual intelligence. It can only handle the modal case. While, real life is mostly full of edge cases.