Why does Siri don’t wish Happy Birthday?

iPhoneX_ ~ Presumably the reason is that the standard Siri program doesn't contain the necessary computer code to check your birth date and generate text-to-speech birthday wishes.

However, you can easily set up a Personal Automation in Apple's Shortcuts app triggered by Time of Day which repeats daily:

And set the Ask Before Running switch ON so you don't miss Siri's birthday greeting.

Shortcuts User Guide for iPhone and iPad

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According to me, it is inappropriate to wish someone Happy Birthday without knowing current facts about the person's state of mind and circumstances that they are in.

iPhoneX_ ~ Correction: Set the Ask Before Running switch OFF so you aren't also asked each of the 364 days when it's not your birthday!

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