That is exactly what Shortcuts will help you do (to a degree). Developers can 'donate' (Apple's term for it) the activities that you perform in their applications. "Siri" will attempt to figure out when you perform this action most often using time/geo data and suggest it on the lock screen or search screen. This could also prompt you to add a voice trigger for this action, thereby 'teaching' Siri more.
After reading your clarification, and reflecting on this a bit more, I think Siri might actually have a chance to impress. What came to me is that I sorta have a per-app ToM for Siri (which i suppose parallels humans being good at some things and bad at others). But what I realized is that...
Siri is a cartographer. It seems like she has good domain specific mastery of maps, directions, places, etc. and not to mention, she might even have have an thin (but growing )representation of her own, about my desires and what I know and dont know when it comes to geospatial logistics. In maps Siri really shines, right? I could say something like "Siri, where is the nearest Jack-in-the-Box" and via Maps she say stuff like - There are two Jacks within 3.1 miles, but you might also be interested in knowing there's an In-n-Out and a Shake-Shack nearby as well. In-in-out is currently not as busy as it usually is this time of day, and examining traffic patters I've formulated a shortcut. Should I give you those directions?
Then a few min later I might be eating a double-double and say "Hey Siri, how much memory do I have left on my phone?" and she will reply "Sorry I can't help you with that" (the actual response I got to that question just now). Know thyself Siri! Anyway, it's just stuff like which makes it so difficult to pin down what she is capable of.
But I'd be satisfied if Siri were to master of a few more apps in a domain general manner. That way I can continue avoiding the rote memorization of commands and simply rely on Siri being a domain general boss at this or that app. Paticularly for other use-cases where (as in maps) it actually makes sense to get and recieve info via voice and not simply interacting with the screen.
