Google's assistant might be striving for more openness, but I don't have high hopes here either; at least until a formal development kit is released. Given that Google won't be able to use its same tried and true ad revenue strategy, we can expect them to offload voice requests to the highest bidder or prefer Google services above all else. This is another perverse link into Google's realm of anti-privacy; but worse, because they won't be able to do ads along the side. The responses will be the ads.
All of this to say that all of these locked down digital assistants will fail until a company truly approaches it from an open and wholistic perspective, and one that doesn't rely upon troves of private data. These devices may sell well this year, but so did digital picture frames. How many of those are still in use?