Although hemp played a major role in the early development of North America, it was eventually overshadowed by cotton. Hemp harvesting was extremely labour-intensive. When the
invention of the mechanical cotton gin at the end of eighteenth century made it easier to process cotton, hemp could no longer compete. Traditionally, Hemp was processed by hand which was very labour intensive and costly, not lending itself towards modern commercial production. In 1917 American George W. Schlichten patented a new machine for separating the fibre from the internal woody core (‘Hurds’) reducing labour costs by a factor of 100 and increasing fibre yield significantly.
Mr Schlichten and his machines disappeared, not surprisingly!
From < https://www.totalhemp.co.uk/history-of-hemp/>