> I think a lot of the reason it failed is concerns with privacy.
This is a big part of it for me. Every social network is yet another place where my personal details get plastered on the web. I don't really want that.
Google Docs, Google Drive, gMail, whatever. I like most of them, and gladly offer up my personal details in return for useful services. Google can target me for ads all day long, as long as the relationship stays firmly fixed between ME and GOOGLE.
I'm glad Google+ is dying. I started to resent it because Google tried to stuff it down my throat. For instance, take giving an app on the Play store a rating: Before, it was simple: enter a number of stars, and move on. Suddenly, one day I was informed "You must have a Google+ account to do this." Why? Why? WHY? It served no purpose, nor did it add value to the process in ANY way. In fact, all it did was give me yet another social network I had to lock down to keep my online privacy somewhat intact.
I tried Google+ when it launched. I didn't like it. I deleted my profile. The fact that they told me I HAD to turn it on again, for absolutely no good reason, just annoyed me.