I'm aware of PRISM, though I misremembered that Amazon was involved too.
Still, I'd argue they are absent because they store little of the things the NSA cared for at the time, reference slide 3:
https://en.wikipedia.org/wiki/PRISM_(surveillance_program)#/...
Amazon at the time didn't have widely used social media, personal photo or video storage, person to person chat, email, etc. The basic info input by people was already collected via all the other companies. What does the NSA really gain from the Amazon dataset at the time?
I bet if Alexa was out and the NSA wanted data from these devices, however they got the rest to agree would have applied to Amazon. I'm inclined to believe it was pretty unavoidable extortion. That said, I hope that Apple / Google / Amazon can temper assistant always on recording by not doing it, let alone sending to a server. If they don't have the data it's hard to turn over when extorted.
Still, I concede my NSA standard looks to be failed by Google. That said, Google or Alexa, they have it all anyways, and I don't believe for a second that if the government decides to use these types of devices to collect voice data that they all won't take the same stance, whatever it may be. At that point, I'll be unplugging whatever one I have any serious conversations. Heck, I already do that to be safe now.
I'd still point to the industry breadth of Amazon as a concern. Though, these posts illustrate pretty well that privacy is a lost cause for most cases, or at least one technologically agnostic within our current major choices. Noted in case the Alexa / Amazon ecosystem improves.
#/media/File:PRISM_Collection_Details.jpg){kind=link}