Anyone else remember when Apple announced they were “opening up Siri”
Yep, but let's get real. SiriKit has never opened up, and never became useful for development, especially when you compare Siri to the competition. Siri has a major problem when compared to both Google Assistant and Amazon Alexa. Those two allow server side apps to be developed, and run on any hardware, including cars, watches, toasters, smart displays, SBCs, phones including iOS devices, and the list keeps going, and going. Apples Siri is only on Apples Macs, iPads, iPhones, Apple watches, Apple TV, HomePods, and the iPod Touch devices. That list of hardware is severely limited when compare to the other voice assistants. What really hindered Siri was SiriKit was fragmented on Apples own platforms. If you made a SiriKit iPhone app, then you had to add in support for Apples watches as well. With the other voice assistants you write your voice app once, and it works on Android, Android Wear, Android Auto, (iPhones, iPads with one of the other voice assistants installed), Macs, smart displays, smart speakers, and lots of other hardware.
Siri Shortcuts is a kludge, and not really a development platform.
What Apple needs to do in order to compete, is they need to make Siri a server side product. Even though Siri for the most part has always been a server side product, because users requests are always sent to Apples Siri servers to get processed. This is where Apple needs to make a back end for Siri apps. That way those apps are not tied to any hardware, just like the other voice assistants.