In the narrow hallways where media moguls trade in brutal trash talk, David Zaslav’s move to split Warner Bros. Discovery into two companies — studio and streaming on one side and Turner-Discovery cable channels on the other — is being judged particularly harshly. Sure, say Zaslav’s peers, decoupling the streaming and content-producing side from the declining linear world makes sense now. NBCUniversal just did the same, spinning off its cable channels into a new entity, Versant. Lionsgate has