“Corporate America” is not monolithic. It has always been possible for any faction to have its own media. For example, before there was social media, there was radio and TV. Before that, there were newspapers. Even in the 1890s, it wasn’t that huge a capital investment to set up your own printing press. Nowadays, it is not hard to set up your own social media site. Parler is too stupid to do it, and continue to depend on outside vendors (I’m not sure I’d feel very secure under the “protection” of the Russians; there are a lot of eastern Europeans who can explain the problems with that). It’s not really that hard to set up a streaming TV network, at least in terms of technology.
One of the issues here is that it further bifurcates where people get their news. And we are already at a point where the core right wingers already have their own model of reality, which treats the rational one most of us adhere to as a threat. (We consider the right wing reality to be a mental disorder, which may put us at a disadvantage.)