The foray of Amazon into healthcare is not recent. It's mostly seen as an enormously worrying move from our European perspective, with a fair lack of culture regarding the U.S market.
First, let's state what should be obvious: Amazon, just like Apple, Microsoft, and Google WILL enter the healthcare market. The reason? It's one of the largest U.S. domestic markets after defense (in which some are already discrete actors), and it's probably one of the most economically inefficient markets on the planet.
The sad state of American healthcare
A few numbers to understand: