Instead, the new Gears run Tizen, another open source operating system that Samsung, Intel, and others are working on. It is starting to look like Samsung wants to distance itself from its reliance on Google for software and services.
Samsung’s official reason is that Tizen has better battery life and performance. The new Gears can get up to an extra two days of battery life by running Tizen, even though they have the same size battery. The Galaxy Gear barely made it through a day on one charge.
To be fair Android isn't optimized to run on wearable devices like smart watches, but Samsung didn't want to wait around for Google to catch up. It was clearly concerned about beating Apple to market. So far Apple has not shown up.