There's more than a little evidence that Google is working on making Android Wear smart watches work with the iPhone. In what seems like an unholy partnership, iPhone users would get what would appear to be very similar functionality with Wear that Android users do.
Whilst it may be possible for Google to make the Wear work, the question I have to ask is will Apple ever allow it into the App Store. Logically the answer would have to be no. Why invite the hungry lion into your cave (or more accurately walled garden) when he could eat you and your lunch?
So, although Apple has allowed other smart watch manufacturers to deliver their companion apps from the App Store there's no guarantee it would allow Google to do so.
There is one reason why Apple would allow it though. To smooth the way for Android switchers moving to iOS. There are a small but significant number of Wear owners. Allowing them to use their watches with an iPhone makes the purchase of one so much easier to justify.
By the same token, Apple could look to make the Watch work with Android. Sounds crazy, but it's not unprecedented. When Apple made the iPod compatible with Windows the same principle applied. Make the best product in its class available to as many users as possible. Reap the rewards of higher sales and prompt customers to switch to the all-Apple experience as a side-benefit.
It's unlikely to happen any time soon, not least because Apple is going to spend the next year to eighteen months selling every Watch it makes.
In time however, the capacity may be there to allow Apple to stalk the lion in its den.