Taxpayer dollars and regulators' attention are rival commodities. There are plenty of monopolistic/oligopolistic companies and industries that merit examination

Taxpayer dollars and regulators' attention are rival commodities. There are plenty of monopolistic/oligopolistic companies and industries that merit examination and reform much, much earlier than Amazon because they currently are exploiting their market position (Chicken companies, Monsanto, etc.) If no mono-/oligopolies existed that were abusing their power, then maybe our government could talk regulation Amazon, but still you'd have to make a strong case. I think it's a tough sell to have an inefficient entity that does not have to compete in a corporate survival sense (the government) tell a very efficient entity that has seen many similar "monopolies" fall (e.g. microsoft) to act differently.