I know that many of you have Google or Alexa in addition to Siri. If that's true for you, you may have noticed that Siri seems to be more limited in its capabilities. While Apple has made some improvements by opening up Siri to some app developers, you wonder why Siri's capabilities as a voice assistant have not caught up to those of Google or Alexa. For instance, Siri can work with Apple Music, and you can control your phone, but if you want to open a book in Audible, you can't do that.
If you feel Siri could use some upgrading, I'd encourage you to contact Apple to express your thoughts. Thanks.