Alexa is available for all Android devices.
Prime Subscribers already get unlimited Photo Storage and ridiculously cheap ($50/year) truly unlimited Cloud storage accounts.
Sure, you're trading your privacy off to a different internet giant, but if I'm looking for the particular feature set available with a Pixel phone, it seems like I can get them just fine from Amazon's apps and services without having to buy Google's phone in particular.
Likewise, I already know the Pixel doesn't have hardware features I legitimately want to see, like a card reader and a removable battery. I'd rather get the hardware I want and mess around with adb commands to kill the handset/carrier vendor's bloat than deal with hardware that's inadequate to begin with.
This doesn't seem like a compelling option at all and is even less so for trying to create exclusivity in the OS.