Users may often not see the app – that's kinda the purpose of voice commands. But the interface isn't replaced by an Apple interface, its surface is simply reduced.
You'll say 'Facebook message mom' or something like it, and it's going to message mom. You won't see the FB logo, because you won't see any logo. You may see more your mom, though.
In fact, third-party apps will profit, because they are no longer second-class citizen compared to Apple-provided apps.
There are certain tasks that are predestined for Siri – such as starting A Nike+/Runkeeper/etc. run: easy one-shot commands that replace unlocking, navigating, opening, menus etc. I'd suspect if this were a major conspiracy, Apple would have opened the API earlier.
But think of this as a step towards commoditization of services. It's a small step from "Hey Siri, get me an Uber" to "Hey Siri get me a ride", whereupon an Apple bidding algorithm gets you an Uber, a Lyft, a GrabCar, etc. based on e.g. price, wait time, and reviews. As a user, I wouldn't necessarily care which platform got used as long as it meets my need.
ios hasnt previously let you set a default app for protocols or filetypes.
As an Android dev familiar with Intent style interoperability, I simultaneously detest and envy Apple's hand built APIs.
Android is great because apps can talk to each other with intents. Your app sends the "I want to take a photo" Intent and default photo app will handle it and return you the photo data. Simple right? Except you're talking to third party code and the request and response format is so flexible its very hard to check that you (or the other app) have implemented everything correctly. Did you specify the front camera or the back camera? What does no specification mean?
Its the burden of freedom.
Voice (and messaging) are constrained interfaces, so you need to put more horsepower behind them to help them work and become interactive.
The golden jail is getting a new door.
- This is opening a previously private API for third parties. I fail to see how this is, if anything, going to make them more competitive with Apple-provided apps.
- If golden jail is getting a new door – doesn't that actually mean more freedom?
How do 3rd party keyboards fit into your narrative?
Paraphrasing, "Apple puts the user in a prison... But its a very beautiful prison."
Apple is taking control of the user experience with third parties. It's the next generation of the "portal" concept. Expect to see Apple standards on what your API needs to look like.