You can do it today with the action button and various apps (including OpenAI). And I believe you could do it a year ago as well.

This is what Apple would say, but it’s not the same. To activate the shortcut I have to unlock the phone whereas Siri works in any situation.

The friction of one button press to 3-4 interactions is significant enough to make it not worth the action button, especially since holding the power button is supposed to do the same thing.