It was just announced not to long ago that Nest will be merging with Google. I think this is a key indicator that Alphabet plans to make make google even more competitive in the smart home technology sector. Apple is way behind on this, and most likely will be missing out on this market for a long time, especially with a delayed release of its HomePod. Something that these companies will have to consider moving forward is the ease of access for developers. If one product is easier to develop software for than the other it is likely that the product will have more features and functionality. An example being other companies like the few you mentioned above being able to integrate their IoT devices using googles smart home API. I think as this tech becomes more convenient and affordable for users, we will begin to see mass adoption.