because of the system at that time, it was mainly the big landlords, respected nobles and bureaucratic groups in the south of the Yangtze River who controlled the handicraft industry. Profits mainly depend on privilege tax exemption, tax evasion and smuggling. The way of competition is mainly an accessory to the struggle for power, but there is no requirement for the development of rival industry itself.
The feudal system didn't guarantee private property, let alone recognize technology patents, which was the biggest reason why the global feudal era generally restricted the development of handicraft industry and marched towards industrialization.