I do think it has because social media is not only ruining old fashioned ways of media like newspapers etc, but also ruining friendships and stopping communication between people. It also has ruined self esteem and self image of people using social media as it trending to do stupid things, like cut4bieber, which got way out of hand. Also the London riots were impacted by social media, thousands of people got involved in criminal activity, which would have never of happened if social media hadn't been used.
Because its exclusiveness, as most sites do not allow the transfer of information from one to another and there is no reliability of information presented and there are issues with trustworthiness and also social media creates more unwanted interaction. Mostly people hardly meet each other because they are so much attracted to it that face to face interaction has decreased very badly.
Social media and mainstream media both seem to be working fine and how they were intended to work. Some people enjoy watching or paying attention to both social and mainstream media. Just because both are existing and social media has gotten larger does not mean that mainstream media is getting smaller.
Social media has certainly taken a toll on mainstream media, and has sort of left it far behind in its tracks in a lot of ways. People's first front of information seems to be social media, and I don't see this changing any time soon; however, mainstream media has not, in any way, been "ruined"; only been pushed to the back seat.
Because social media can very quickly focus the attention of a large group of people on an issue, it can have a direct impact on mainstream media coverage. During the presidential election process, for example, social media was "trending" during every debate, primary and major speech made by either candidate. Media personalities and news reporters all maintain social media accounts, so they receive immediate feedback on their coverage events and stories.
I think both have pros and cons, but neither one kills the other. Some prefer TV, some don't. I don't think either one will ever be ruined. Though social media can drone on and on, I think people prefer to hear news rather than reading it. I myself prefer no media.