It threatens their business if customers aren't comfortable having products delivered at home.

But obviously it's a new revenue stream with myriad additional business opportunities for Amazon to capitalize on the paranoia of its customers WRT having their packages stolen, to sell surveillance products to them (and access to law enforcement, ad/marketing interests, etc.).

No it isn't unless it's signed for. Even if a video / photo is taken that doesn't prove the person taking the photo took the package afterwards.

The drivers are not always malicious either. Sometimes it's bad training and/or user experience on their equipment.

I had several packages delivered which were "signed" for by someone named "through the letterbox". Similarly, one package said dropped off at the door/porch but no sign of it so I asked for a refund as I assumed it's been stolen... 2 days later my neighbour gives it to me because it was actually delivered to them, but the delivery person couldn't select the proper option to let me know so I had no idea.

My delivery status with Amazon is frequently something along the lines of "left in the mail room". I live in a free standing single family home in a neighborhood where every one has their own mail boxes.

They don't actually care. They usually eat the cost and send you another one. I guess it's cheaper than the cost of requiring signatures, at least once we're constrained to the subset of the population who can order things online.

I bet someone identified this as a substantial line item that was trending up and they want to push Rings out into the world to try to deter future growth and losses. Who knows... the acquisition might have paid for itself in cost savings.