Earlier quoted context omitted.
We have many like Google plus, twitter, linkedin, reddit and even hacker news (catering to a specific niche). Problem here is that too many people whom we may call "less tech savvy" won't leave FB. So, in order to stay "compatible" with them, we need to keep our FB accounts active!
Reddit and Hacker News are rather content aggregators rather than social networks. Google+ and Twitter have the same issues than Facebook on these specific issues. LinkedIn is a bit too specialised for professional messages and they too like Google+ and Twitter don't have a great track record concerning privacy and abusing their position.
It's well past being solely an aggregator.