Unfortunately that is a negative on that question. In a statement provided to 9to5Google, the company confirmed that Google Assistant will remain an exclusive to the Pixel phones for now. “There will be certain features — such as the Google Assistant — that will be unique to Pixel before we make a decision to offer it up to the rest of the ecosystem.”
Google adds, “With some of these features currently unique to Pixel, we’re carefully experimenting with these changes to assess user reaction and feedback.” Such a move isn’t exactly new. Apple has done it in which with pretty much every new iPhone, the company introduces a new feature that will be exclusive to that phone and future handsets, leaving older devices out.
Siri made its debut in 2011 on the iPhone 4S and was not released for older iOS devices, so Google’s decision to make Google Assistant exclusive to the current (and future) Pixel phones shouldn’t really be that surprising, although hopefully Google will change their minds in the future.