You're right - but this isn't the first time we've heard about this exact practice. It's been reported on extensively, so if anyone was going to investigate something illegal, it would have happened.
It is however, good ground for an Anti-Trust case. Using your position as a market maker to push your own products is literally illegal anti-competitive behavior and can trigger a court order to break up the company.
That argument seems to prove too much? It's sort of an Efficient Market Hypothesis for government regulation, and it would apply just as much to e.g. FTC and DoJ with respect to anti-trust violations as to Congress (as thread parent would like) or DoJ or whomever with respect to fraud or illegal wiretapping. Maybe it would be better investigated by a class-action plaintiffs' attorney, but even the mightiest firms might hesitate to wage the discovery battle that would be required against such deep pockets.
I believe anti trust is triggered when it negatively affects consumers, with Amazon’s aggressive competition consumers usually win. At least short term...
It is however, good ground for an Anti-Trust case. Using your position as a market maker to push your own products is literally illegal anti-competitive behavior and can trigger a court order to break up the company.