Not really irreversible unless they get a monopoly on violence, so as long as the overton window from the publics perspective shifts dominantly towards breaking them up in the future we'll be able to get a better situation.
When you can reliably tell they have a monopoly on violence, it's far to late to do something about it.
However, Very Bad Things™ can happen long before they have monopoly on violence. And violence where? Large companies operate in weak jurisdictions, not only in their home states of Maryland and Ireland.
Well, historically, there have been a number of companies with the right to violence. The East Indies and West Indies Companies, for instance, or more recently United Fruit. I haven't bothered to check, but I'd be surprised if Big Oil didn't have mercenaries on call in hot zones, with little to no oversight.
Nobody (company, nation or gang) needs a monopoly on violence to become dangerous.
Those companies didn't have the right to violence in their home countries, they waged wars in other countries instead. Companies overthrowing their home country hasn't really been a thing.
True. However, please don't forget that the conglomerates being discussed initially do exist and have considerable influence in other countries than the US, so my remark remains :)
Also, the Medici family was initially a wool company, then grabbed power in their homeland, kept it for about three centuries and somewhere along the way produced descendants that ruled over much of Europe. Similarly, the fascist uprising that gave power to Franco over Spain was largely privately funded by a bank [1] and I seem to remember that the German Nazi party was largely funded by industrialists and bankers [2] until reached power.
So, I'd say that companies overthrowing their home country's government has unfortunately been a thing for quite some time.
They (search, social media, advertising companies) are gaining a monopoly on truth. With that they indirectly control the government, which is the one with the monopoly on violence.
To emphasize, all human productions are biased, that's human nature, and news media are not exempt, despite many outlets making serious attempts to produce unbiased news.
Part of the job of being a consumer of media is understanding the bias of what we're consuming, determining whether it skews the news, and possibly counter-balancing by consuming other media with different bias. And yes, it's lots of work and most people aren't willing to spend the time doing that.
However, Very Bad Things™ can happen long before they have monopoly on violence. And violence where? Large companies operate in weak jurisdictions, not only in their home states of Maryland and Ireland.