If we assume it took one hour of cummulative labor to produce (extraction of materials, manufacture, transport, then divided by the number of mugs made), then in an ideal world things like this would still exist. Surely someone who enjoys such a thing would exchange money worth one hour of their own labor for it. Even in the preindustrial era people would spend the meager manpower and resources they have on kitschy things like this. I mean I've 3D printed dumber things as gifts and the 15 minutes of effort I put in it wasn't a great expenditure.