Very enlighten post.

Do I think that Amazon has grown too big? Yes.
Are they providing a service that consumers want? Yes

Something that I always bring up with a discussion of Amazon becoming a monopoly. The markets that Amazon is entering, what are they doing to innovate that field to improve the customer experience and streamline the process?

Everytime that Amazon enters a new market, they are finding a better and more efficient way of how to run that business.

What is the most inconvenient thing about going to the grocery store? Waiting in a checkout line? Not anymore, just pick up your purchase in store and walk out, check out kiosk not required. Better yet, you can order online and have it delivered to your door.

What are these businesses doing to keep themselves competitive with the market? If someone comes along with a better way, of course eventually you're going to lose ground to them.

The market requires you to always grow and keep changing. When you become stagnant in your ways and think no one can touch you, that is when you lose.