“...The market may also be anticipating other companies doing the same thing....”
True. But it takes big money and a lot planning & staff to do it. Many are not in that position like these guys are. OTOH, I think we may see more mergers like the CVS & Aetna deal though.
Another possibility is other corporations could join the Amazon group. Any way I look at it this is going to put pricing pressure on health insurers. They will be forced to offer better value if the Amazon group is successful. I see it as good for the consumer, though.