So, when we talk naively about free markets we commonly ignore the Firm. In industries you have the propensity for cartels to form, or for "industry standards" to come to exist that enable actors to work against the interest of their consumers.

You also get economies of scale that lead to capital concentration, razor thin margins and extreme efficiency reliant on capital intensive business models. As a result you wind up with massive barriers to entry for new competitors, and so the usual "someone will come along and outcompete" doesn't really work. It works when you're selling doodads and fruit, but semiconductors and car manufacturing aren't fruit.

In particular, industries that become foundational to the workings of a society become impossible to avoid engaging in. In the US, cars are a given, you have to have a car. One car company does something and gets away with it with their customers, so the rest follow suit and now you're in an environment where everyone does it and there's no way out. There's no direct collusion here, just neither has an interest in competing on a front because the the practice benefits them both.

This is where industry regulation comes in. It comes in only when it isn't an entirely free transaction between two parties. Where a party must use a product or service, or where competitors collude directly or indirectly, state action is warranted. Examples where the party must use a product would be cars, food and car insurance. Direct collusion is interactive, indirect is passive, such as an entire industry without direct cooperation engaging in practices like this.