Why is a traditional opera adapted for film and television?

Why is it said to be an adaptation of a traditional opera?

Why is it not understood that it is based on folklore, literary writings, historical allusions ......? Most of the repertoire of opera is taken from this.

For example, "Cheng Ying Saves the Orphan" (sorry, it seems like it should be the Peking Opera "Searching for the Orphan and Saving the Orphan" and there was also a later version of "Zhao's Orphan") was originally based on the Yuan miscellany "Zhao's Orphan", which in turn was based on a relevant rendition of Zuo Zhuan ...... The Legend of the New White Woman is about Chinese people's The new White Snake Legend tells the familiar story of the White Snake, and is not a copy of the White Snake Legend of Peking Opera or Yueju Opera.

The same story can be used by opera for creative writing, drama TV and television and even opera and dance musicals. Perhaps the film and television drama in the adaptation of reference to the opera or borrowed from the opera specific situation settings, but can not say that the film and television drama is adapted from the opera.