Leftists tend to not know how to keep media sustainable. NBCnews and Air America are examples of leftists killing media.
Excellent examples of that media. However, Twitter is a different animal with a wholly different dynamic. And I strongly suspect conservatives have not quite a full understanding of the synergy behind it.
Mr. Trump has built his campaign publicity around Twitter. It has been brilliant and effective.
1. Leftist political views tend to have a lot of appeal among losers and misfits who can't read, write or think clearly. So they don't read newspapers and have no interest in political discussions in a media forum. These people also tend to be at the lower end of the economic ladder, so advertisers don't see them as a good target audience.
2. Leftist political views tend to have a lot of appeal among the very wealthy, who would be a good target audience for that reason alone ... but there aren't many of them, so they don't support anything other than a narrowly-focused, specialized business model.