It's not that we can't see them - I literally named some examples. But where is the evidence for your specific claims, because there's plenty of evidence against them. Markets without much regulation are routinely very competitive. Look at the computing industry, which for most of its history had no industry-specific regulations at all beyond the illegalization of hacking - a simple extension of private property rights.

And the effect by which regulation actually strengthens incumbents and reduces competition is well known.

A common problem in these discussions is conflation of different goals. You talk about companies selling "poisonous shit". That's not a competition related goal so has nothing to do with anything I've been saying. It's an environmental goal. Governments often pass environmental law fully accepting that it will reduce competition and might strengthen or even create new incumbents - and they don't care! In fact most environmental law is like that because it's exactly as you say, other countries like China don't pass such laws and out-compete local firms as a consequence.

But that's not a failure of the free market. It's a failure of environmental law. Or, sometimes not even a failure, just a known tradeoff.

As a general rule it's hard to find markets that are controlled by monopolies over the long run without government regulation being to blame. Temporary monopolies can arise naturally and there's nothing wrong with that, but over time they usually fall by the wayside unless a law is preventing that from happening.