What does it mean that a canary in captivity will never be as good as a real phoenix?

It means that those imprisoned women will only be attached to men, not as good as women with ability and strength.

The imprisoned canary is a metaphor for a woman who is attached to a man and lives a good material life, but is bound and deprived of her freedom. Most of these women are excellent in appearance, but they can't be independent in spirit. They are used to a well-fed life and can't leave this comfort zone at all.

The real phoenix refers to some women with real skills who can get what they need through their own efforts and abilities. They rely on wisdom, strategy and pattern.

Therefore, compared with the two, the canary can never compete with the real phoenix, and the two can be compared. No matter how hard life is, a woman should never be someone else's canary, because once this person doesn't want you, you are nothing.