There is no scenario where you are not beholden to some corporate entity, and most likely you're beholden to dozens of them to keep you alive and keep your life functioning at all times. The food supply can be cut off by less than a dozen major corporations, and you will die. Less than a dozen major corporations can choke off the supply of fuel or electricity, and you will die. This is true, in one form or another, in every developed or semi-developed nation on earth. Maybe the government acts fast enough to counter that action by said corporate giants, maybe not. It's a system built on the profit motive being the predictable pursuit by said corporations, meaning they overwhelmingly will not behave that way; combined with the threat of military or domestic armed reaction by their respective government (namely that any tech giant can trivially be destroyed any day of the week by the US Government; Zuckerberg could be in chains in three hours if the US Military decides to do it, there are consequences that prevent that as it is).
What happens in ~1955-1975 if AT&T, at their peak of monopoly, decided to blacklist you from their telephone service?
What happens in 1910 if Standard Oil decides to cut off your shop's access to its oil-related products?
What happens if you're in a small town, with Walmart as the primary goods seller, and Walmart blacklists you? Maybe you can drive somewhere far out of your way, if you can afford to, and replace them as an option. At a minimum it severely screws with your life. There's nothing unique about Amazon there, you can order from other online stores, and it might be a huge inconvenience.
What people think is new with Google et al., is not new.
It rather depends on the reason for the decision to put you on the blacklist.
In general, AT&T was allowed its monopoly power under government regulation. A goal of the Communications Act of 1934 was to provide universal telephone service. Section 254(b) lists the Universal Principles, including (4), "All providers of telecommunications services should make an equitable and nondiscriminatory contribution to the preservation and advancement of universal service."
If your service was cut off because you liked to pump line voltage through the phone system, then they could do that because it's a nondiscriminatory meant to protect the phone service.
If they cut you off because you wrote a letter to the editor complaining about their services, then that's discriminatory, and you could take your complaint to the local public utilities commission or FCC ... or perhaps sue as well; I don't know the regulatory history.
In any case, there was certainly government oversight of what AT&T could do, in terms of putting someone on a blacklist.