I don't have a real proposal in mind and like you I do not think Amazon or Ebay are critical to the stability of the internet.

I do think, however, that the current situation is no longer acceptable. I don't know whether as a society we should consider some sort of limit on influence a given company has, but that is actually what is needed. If Ebay was a corner store, I would not give half a shit that it stopped carrying Seuss. When a publicly traded company does it, it quickly becomes problematic.