The solution to monopolies in Saskatchewan, where the geography is vast, and the population sparse, has been to create Crown Corporations. In Amazon's case, this is their single payment system to reach many retailers, which solves the problem of reinventing the wheel each time a vendor wants to collect payment online and ship goods.
It makes little sense to put in multiple electricity delivery wires, or multiple natural gas pipes to the same locations, so sharing the infrastructure becomes a social concern, especially when a single privately held corporation has that level of basic control. Amazon is clearly too big (to fail, ugh), so what are we going to do about ensuring the public has a hand in making it run equitably?
nothing, unless you want to buy into amazon and try and change it from the inside.
what is the idea of a business running equitably? it has been tried and mostly has failed, or eventually become so successful as to turn into the same old old