It's such a financially convenient line of thinking. It's absolute nonsense. Both at face value and once you dig into it. Mainstream media is feeding us constant lies which work against our interests, destroy our ability to trust institutions and the government. Big Tech is clearly the biggest threat to our democracy.
Before Big Tech, we did not have such problems. This new narrative is pure self-serving propaganda, a figment of the imagination of corporate-funded lobbyists.
Free-market capitalism with freedom of speech is the recipe for economic prosperity. Has been for hundreds of years.
Some people will point to China as an attempt to show a counter-example ("Look at China, they're totalitarian and their economy has been booming.") but they conveniently forget the fact that China's growth has been happening during a time of general loosening of policies. The past 20 years in China have overall been characterized by an increasing tolerance for free-market capitalism and more freedom of speech compared to what it was before.
China came out of an extreme form of communism. Of course, any loosening would yield huge improvements! Also, they have over 1 billion people, of course any small improvement to even a small fraction of their population would have an impact globally.
The problem with the US and the west is not freedom of speech or the free market, it's our debt-based monetary system which is now based on soft money. The decline started in 1971 when USD became detached from the gold standard. It's no longer backed by anything; also, the growth in the currency supply has become unconstrained and the distribution mechanisms for all newly issued currency have been partially hijacked to serve corporate interests. The effects of this were not felt immediately. It's only in recent years that the negative effects of our soft-money system have become difficult to ignore.
The important thing to note is that no fiat system has ever survived more than a few hundred years. A monetary system which is founded on the endless debasement of its own currency is doomed to fail sooner or later. There has been hundreds of such monetary systems over thousands of years; not one which remains to this day. It has never worked and will never work in the long run. They're just pyramid schemes.