I had the thought that the only way to really fight against large corporations and billionaires is to compete against them. Start your own business. Amazon relies on third-party sellers more than anything in their business. So start a business and sell your items there. Don’t have anything to sell? People are a creative bunch, make something. Find a local producer of something and make a partnership to sell on an independent web site.
Which fees will get lowered? Prime? The sellers still have to pay fees to cover it. Amazon won’t care unless the people who are actually paying for everything leave. Be an example and start competing. Doesn’t even need to be a business that sells stuff to compete. Start a blog with talking about sites to buy everything outside of Amazon and Walmart.