Amazon already offers warehousing and shipping as a service, even if you don't sell your products on Amazon: https://developer.amazonservices.com/gp/mws/api.html/180-311...

You ship them a pallet of stuff, and then use a web API to ask items to be delivered to addresses.

Oh, they really have an API for everything. That's awesome. Now... I wonder if there are companies in China that have an API to order a pallet of stuff?

Everything that counts are infrastructure. If you're providing a service that other developers build on you're going to compete with Amazon in the future.

Not only developers. They are also upending all intermediary businesses between manufacturers and consumers (inventory, shipping, etc).

This is a strange question - Amazon can offer anything that can be thought of by the human mind and can be shown to make some money. It's a competitive world. I'd fully expect Amazon to do anything and everything their staff can come up with. Perhaps in a few years when the space industry takes off maybe even run a space / orbital freight service. It makes sense for them.

Re: could

Amazon has offered streaming video for years now. This is just a guess on my part, but they probably don't receive video from studios in a stream-friendly format. Their streaming format has also likely been updated over the years.