Shit media started more in the 70s, and really took off with CNN's advent though.
It got WORSE after the repeal of said law, but the repeal of said law was a result of our media going to shit, and politicians thus succumbing to the pressure from the big media conglomerates, and exacerbated the effect, but wasn't the source cause. Media consolidation was going on before that.
The source cause was media deciding its job was no longer to report the news, but to make it.
The solution, however, is very simple: Bring back trust busting and monopoly busting. Every major corporation in America, from Microsoft and Google to the media conglomerates, could be broken up into multiple small regional entities and prevented from buying up more than a percentage of the market for two decades or so like the phone companies after the break up of Ma Bell back in the day, and no one would notice a difference except in better prices, better service and more competition, and it would solve so many problems with the way our system is working right now.