Because, in the mid- 19th century, Britain’s working classes sported caps slouched rakishly to one side and its upper classes preferred them for casual pursuits, cloth caps commanded quite a market. In fact, relates Bill Williams,
Cap making was the boom industry of the late 1840s and 50s. The first in the field as entrepreneurs…rose rapidly on the economic scale. …Successful retailers in other lines…switched direction to cap making on the basis of immigrant labour. More resilient paupers…found in cap making the means to substantial independence…