I agree with you Abi, for the most part, but you don’t mention the trend — which is that the regular “MSM”, particularly newspapers, are in terminal decline with diminishing circulations. The circulation of The S*n has almost halved since 2010. Many of the paid-for dailies seem to be losing 5% a year or so and if anything that’s speeding up. TV news audience is also down.
Sure, newspapers have websites, but it’s a crowded online marketplace, and much harder to compete for eyeballs and the traditional press tend to have less influence amongst online audiences than they do in print.
I agree that social media is a series of bubbles and echo chambers, the power to ignore and hide people/views you don’t agree with is much more sophisticated than the old method of simply choosing a newspaper. But it’s still going to be a game changer. By the time of the next scheduled election in 2020 it’s likely that the main daily papers will have lost another third to a half of their circulation. Others will follow the indie and go online only. So whilst the traditional media is still going to be important, it will become increasingly less so.