While there is a lot of truth in what you say, there are aspects, such as the wasps that deal to many butterfly species. In southern New Zealand it is not easy to attract beneficials to an urban garden. The aphids of asclepiads ignore pyrethrum daisies, nasturtiums and other 'attractants'.
Breeding beneficials is as big a task as the object of conserving butterflies!
While there is a lot of truth in what you say, there are aspects, such as the wasps that deal to many butterfly species. In southern New Zealand it is not easy to attract beneficials to an urban garden. The aphids of asclepiads ignore pyrethrum daisies, nasturtiums and other 'attractants'.
Breeding beneficials is as big a task as the object of conserving butterflies!