The truth is, that for the majority of household and personal functions, “human scale’ measurements are actually superior to metric measurements. At present, human scale measures are used for human scale work, and metric measurements are used for scientific work. And there is a good argument to make that this is the optimum.
For example the mercury scale and pound do not require fractional representation in order to represent sensory differences. In other words, the Celsius scale and the Kilogram are less precise than their human scale competitors, and must resort to fractional representation. There is no material value to the C scale, that is within human perception.