The Apple Watch is physically and technologically limiting... hence watchOS. If you have to wear an accessory to an accessory in order to match the iPhone, I’m not sure what you’re really solving here.
I know you love your wearables, but can you be realistic for once?
For now. iOS also started out very limited, but look at what it can do today compared when the iPhone was first released.
Maybe I wasn't being clear enough. My point is that you would be able to not only pair your Apple glasses to your iPhone, but also to your Apple Watch as well. The reason for this is that you might not be able to bring your phone everywhere you go with you. An example would be when running, where some people might bring only their Apple Watch along with them to track their exercise, leaving the phone at home.
The larger point is that having distinct wearable devices designed to excel at certain tasks, and worn on different parts of the body, will ultimately offer more value than having one device be merely adequate at a lot of different things.
The task coverage the iPhone has over the watch is immensely understated by your views.
I would argue that it more the Apple Watch will take on some functionality of the iPhone, but also be given functionality that the iPhone cannot (and will never be able to) handle. Such as health monitoring. Likewise, the Apple glasses will probably also be positioned to take on certain tasks from the iPhone and perform them better (namely AR-based use cases).
So here's how I see things happening in the future.
1) Apple glasses is announced, initially needs to be paired to your iPhone.
2) Apple Watch goes on to become more powerful and ultimately gains independence from the iPhone at some point (probably sooner than later). At this point, it is capable of supporting the apple glasses on its own.
3) Airpods would be positioned as the best way to control sound on the go, similar to how home pods is being positioned as the best way of controlling sound at home.
4) Apple goes on to announce other wearable devices (maybe even smart clothing?) that is capable of pairing with either your iPhone or Apple Watch, but the point is that by the time this happens, the watch is more than powerful enough to stand alone and handle these functionalities on its own.
You may have a point that apple glasses might even cannibalise some other products, but I guess Apple will be fine with losing sales to another one of their own products, rather than to one of the competitors.
