Any free, unregulated market will eliminate competitors until they create an oligopoly or even a single monopoly. It's an immediate consequence of the rules of the market.

That's simply false. Name one unregulated market where this has occurred.

The U.S. before antitrust laws existed.

https://en.wikipedia.org/wiki/Standard_Oil

https://en.wikipedia.org/wiki/Carnegie_Steel_Company

https://en.wikipedia.org/wiki/Southern_Pacific_Railroad

Standard Oil: Its monopoly was already crumbling before antitrust action. By 1911, market share had plunged from 90% to 64% as competitors like Gulf/Texaco emerged and new oil fields broke its grip.

Carnegie Steel: Government intervention. The federal government imposed steep tariffs on imported steel, shielding domestic producers like Carnegie from foreign competition. Without those tariffs, cheaper British/German steel would have kept Carnegie’s dominance in check.

Southern Pacific Railroad: Government intervention. The federal government gifted it, through the Pacific Railroad Acts, millions of acres and subsidized loans. This state-sponsored land monopoly let it block competitors from critical routes.

Google. Microsoft. Facebook. If it weren’t for antitrust, there’d be a lot fewer cell phone companies or airlines. I mean, it’s harder to name an industry where there hasn’t been consolidation. The only thing stopping it is the law. Consolidation was basically illegal until the 1980s. If you wanted to grow, you had to compete.

Wrong. Also, none of the companies you listed are monopolies.

Google was literally declared a monopoly by a court recently. Facebook and Apple both are oligopolies or monopolies in certain market segments. Apple has a monopoly on app store and on device payments. These things are bad enough that they’re being litigated.

Despite constant moaning about the US not engaging in monopoly-busting anymore, that doesn't actually seem to be a problem in practice.

In reality, comparative advantage and specialization dynamics do not uniformly equilibrate on monopoly markets.

The content of the article shows that it is still a problem. You think that landlords and food suppliers colluding to raise prices to just below the breaking point is not a problem?

It's not a "breaking point", it's the market rate. There's no landlord cartel; anyone can easily defect and lower their own prices.

The entire food production and provision supply chain has razor-thin margins. If you're hyperfocusing on that industry, it's a sign that your heuristics are pointing you at the wrong things.

Cartel price fixing is not "market rate" by any honest definition.

Outright monopolistic pricing is also "the market rate". Frankly, virtually any price somebody is willing to pay is almost by definition "the market rate". It's a meaningless defense for an artificially high price.