We have to remember that when we talking about giant companies we are talking about giant institutions, of a form and culture that has not existed in human history. The closest parallels common throughout human history are armies.
I think that our 20th century paradigms have failed to understand and shape these institutions, each with their own trappings. Labour unionism, which was deeply rooted in man labour cultures and many countries' political systems was amazingly corrupt. They became their own institutions layering their own dynamics and interests into the already impossible mesh. The results were far from unanimously positive.
Liberal-capitalism nurtured the concept of non natural person, corporate entities. The cultural relationship between individual, employers, consumers and investors and the institutions is grafted onto the idea that the institution is a legal person. At this point, companies are far more than risk sharing and limiting devices. They are institutions of the same gravity as churches, bureaucracies, aristocracies and such. They are entrenched. I don't mean that in a strictly accusatory sense. They are just part of the web of culture, laws, economies and everything else.
First of all, we all need to have the humility to understand how little we know about how these things work. We are designed to operate within social institutions, not to build and destroy them each generation. No one built feudalism or poleis. No one really designed the international system of nation states. No one created Danish national identity. These things just evolved. Those are the kinds of things we're dealing with.
I don't know what is the right way of dealing with Amazon, Google or Walmart as a (global) society. I think I would be more comfortable if the times brought around a period of miniaturization, where these mega institutions gave way to hundreds or thousands of smaller ones.
For Amazon, what's keeping them huge is (a) dispatch & postal delivery is surprisingly hard. (b) The chain between design, manufacture, marketing and delivery is surprisingly cumbersome. Amazon is a company that does what a market would do in a world fewer impediments.
Maybe the next few decades will make global delivery trivial. This would enable products to come directly from suppliers and simplify the chain. Software developers once had to sell software through software stores. The modern incarnations of software store is a relatively thinner layer. Producers are closer to consumers and the intermediaries are really just market makers.
PS: Price controls have a bad track record dating back to Roman times.