As a first approximation, about 20 years before the end of each century: pre-1880 for newsprint & pre-1980 for television. All that is required for the press t

As a first approximation, about 20 years before the end of each century: pre-1880 for newsprint & pre-1980 for television. All that is required for the press to function is that someone foots the bill. They can do so for a variety of reasons. Supported by a political party (Fox is actually returning to earlier times here). Supported as a charity / pet project (the news barons, Bezos). And supported commercially from sales (CNN). Generally, every news media form in the US has eventually moved to the last.