Google+ was a top-down, scrambling response to Facebook's meteoric rise. I think it ultimately failed because it didn't naturally mesh with or arise from Google's natural strengths.
Google has always had amazing scientists and engineers working for them, but building a new social network requires less math/science and more of a human focus. (Of course, Facebook's data centers and ops are now the 6th wonder of the tech world, but that came later.)
It failed in my case because it polluted every other Google property - search, YouTube suggestions, etc. I'd prefer that suggestions and search results be based on my preferences and not those of an idiot cousin or a foaming-at-the-mouth prepper I happen to work with.
When it launched it was terribly incomplete.
It didn't even have events, which for a lot of people is a mayor reason to use Facebook and they could have even integrated it into Google calendar.
Events were eventually added much later (like a year after launch?), but at that point interest had already died down.
Why they did not delay the launch until it had parity with Facebook's core features is beyond me.
I didn't mean that particular ordinal literally... personally, I'm impressed by how they're able to achieve such a high level of uptime, data integrity, and near-realtime communication.
Google has always had amazing scientists and engineers working for them, but building a new social network requires less math/science and more of a human focus. (Of course, Facebook's data centers and ops are now the 6th wonder of the tech world, but that came later.)