I definitely agree with what you’re saying; we can use social media to incite change within society, but once we feel that the immediate threat has been eliminated, our fight or flight response tends to dissipate. We focus on what is immediately pressing; what comes to my mind is the public outrage over SOPA, PIPA and CISPA. When people thought that their access to certain websites was going to be restricted and that they might face criminal charges for posting things such as fanart and fanfiction, they cried out and protested. Anonymous got involved and, in addition, many websites that were in opposition to those laws participated in a blackout where their website was unavailable to anyone for a certain length of time.
What I find interesting, is that once the law was deigned unconstitutional and subsequently eradicated, people ceased their cries of protest. Internet users, thinking that the threat was gone, sat right back and began reblogging cute memes of cats once again.
But the threat wasn’t gone; after the initial enormous protest on the programs, US and global governments decided to try and bring the bills back, each with less protest than before.
So I completely agree with you; you have to light a fire under people’s asses to ever incite a response.