Why were many of the best crafts and whatnot lost in ancient times?

A lot of good crafts were lost in ancient times, I think there may be the following reasons:

Because in ancient times there was a lot of war, and conscription, and the ancient Chinese thought that skills are passed on to men, not women, so skills will naturally be cut off,

During that period, the status of the craftsman is not very high, and it can only be used to support their families, and it is not valued by the court society

With the spread and influence of the imperial examination system, people began to aspire to change the status, and the accompanying is a break in the transmission of the crafts.

With the spread and influence of the imperial examination system, people began to aspire more to change their status, accompanied by a break in the inheritance of crafts.