There are plenty of examples of state regulation in the greater interest, pharmaceuticals being an obvious example, road safety another. It is not in the greater interest of society to allow businesses to trample over each other or to do as they wish.
Amazon is acting to the detriment of a large number of industries and ultimately to people in general by stifling competition and by being monopolistic and abusive.
> Oh wait... it was tried 90 years ago and it didn't work out.
Whether the current system is working is up for debate.
I don't have a problem with such "monopolies", because they aren't real monopolies. As long as the market is still open to new participants, then it's not really an issue. For example, if a monopolist starts raising prices and hoarding supplies in order to artificially elevate prices, then new participants can enter the market and make money off the delta between the new prices and the old prices that made sense to the market.
Amazon's prices trend downward, constantly. Amazon is also itself a market facilitator, agnostic to which products sell, so long as they sell. High quality and low prices race to the top of customer ratings. Third parties sell on Amazon as well, providing a global market for local brick and mortar shops. Further, Amazon is by far not the only website selling things on the internet. The internet is pretty great at lowering barriers to entry.
There's tons more I could say on that subject but let me skip ahead to what I think the problem is in the US today in regards to worker wages. I don't think it's a problem of some inherent evil in the free market. Rather I think it's a symptom of excess regulation and taxation (and other costs) and a poor educational system, among other factors. The cost and complexity of living these days is much higher than it used to be. There are so many bills, so many taxes, and so on. The bar for a "reasonable" living is much higher these days, and much harder to obtain, with more pressures from every direction on savings and discretionary income. More so, the increasing costs combined with increasing necessity of higher education has put a lot of young workers in a financial pinch, as did the latest housing crisis. People aren't getting the skills they need to build strong careers and to have greater negotiating power. People are being discouraged away from trade schools and funneled into liberal arts colleges. People are being saddled with huge debts in exchange for skills that don't go far in the marketplace, they're discouraged or prevented from saving, they're discouraged from creating their own work (unless they're in software, which is the rare exception) by starting their own companies. All of those things were on the table for previous generations. Without them we've ended up with a generation of workers who are desperate to find and keep a job, who must rely on working for a big corporation because they need that surety of a paycheck to pay their high costs of living and their debts. We like to imagine that all these regulations and taxes have no negative consequences because they were created with the best of intentions, though that's not the case.
But every element there is amenable to improvement, without resorting to marxist wealth redistribtion. I would posit that the consolidation of wealth we have been seeing is not the cause of the problem but rather the symptom of a larger underlying problem.