Older works often conform less closely to the tropes, because the tropes weren't established at that point. When a medium or genre is new it often goes through

Older works often conform less closely to the tropes, because the tropes weren't established at that point. When a medium or genre is new it often goes through a Cambrian explosion phase where there are all kinds of wildly varied pieces, and then things settle down and coalesce on the specific approaches that have proven successful.