RSS peaked in 2006 and has been dying since. I suspect it was from the rise of social networks. Though not a replacement feature-wise, social networks have been competing for time and attention from users since day 1, and RSS readers lost. Google Reader was too late to a declining trend, and it was just a matter of time before it was going to get killed off anyway. http://www.google.com/trends/explore?q=rss#q=rss&cmp…
Using Google Trends to try to divine how "alive" something is is fruitless, as the graphs you get are displaying the percentage of all internet searches that that use that term. Since the internet is constantly growing and new terms are being added all the time, it is impossible to say whether a declining graph on google trends means that absolute number of searches are going down or up.
The point still stands: share of web interest in RSS has still been displaced by other ways of spending time. Whether it's social media, Netflix, or cat photos, RSS simply hasn't grown with the rest of the web.