If Apple builds an iWatch, they will tie it into the iOS ecosystem. This is why Leo Laporte the host likes the Pebble – it works with all his devices.
How many people are Leo with an iPhone and an Android phone? And whatever else is compatible with the Pebble? End users (consumers) usually have one phone. There’s nothing wrong with the iWatch to be tied into the iOS ecosystem — its an awesome ecosystem. Soon you may get cars with iOS on it (just like you can get cars with Linux on it).
The iWatch if Apple makes one will probably be compatible all the way back to the iPhone 4S. It should cover most iOS/iPhone users. And just like the apps you buy in the app store when the iPad came along (first you had iPhone only apps, with double-size; then you had separate iPad apps that would cost more; nowadays many apps are “universal” to work on both and cost the same), I expect something similar will happen with the iWatch.
That said, I like my analogue watches. I had no interest in the Pebble or the Samsung Galaxy Gear. I’d be interested to see what they do with version 2, which has Tizen (even less apps maybe?). When Apple releases an iWatch, you can be sure I’d probably buy it — I have seen things from all sides, and I like their ecosystem.