Google+ always had a weird broken interface and they just never finished it. I was one of the geeks that flocked to it, and had plenty of friends there. It didn't fail because of network effects, it failed because they stopped working on it before it was finished.
It was really strange and I always assumed at the time that Facebook and Google had come to some agreement behind the scenes.
It really was strange, continues to be, the way Google wanders away from products before finishing them.
I get ditching things that don't work, but G+ is a great example of something that had plenty of traction in it's early days and, as far as I can see, lost it purely because G didn't seem to care about it.
Can you elaborate on what you mean? From inside Google at the time, the general consensus was that they cared too much about it, at the cost of much of the rest of the company.
From the outside it appeared to be a bare framework that was never fully developed.
I didn't use it often but I checked on it periodically just to keep up on what was, hopefully, going to be a contender in the social media world. What I saw was almost no change in user facing functionality over the course of it's existence.
There also didn't seem to be any significant attempt at marketing, monetization or collaboration with the community.
Meanwhile there were significant influencers and content producers with large numbers of followers. The dream of any social media company.
I always assumed it folded because they couldn't agree on a path to monetization.
But from the perspective that they actually did care about it (which I read as they devoted significant resources to it even if that didn't translate to anything that was publicly visible)... It starts to sound more like a company that's hit the self hobbling critical mass of size and internal bureaucracy.
People were generally pretty irritated (as was the public) by the integration of every Google product into it. Leadership (both internally and externally) was pretty clear that it was meant to be a platform, one that unified all of Google's products with a shared social layer.
I worked in research at the time and have never been a heavy social media user, so it didn't really affect me much, but the internal story seems to fit reality more than what you're describing: the change in user facing functionality was progressive integration of Google products (like YouTube)
And Google broke their social network that was actually working (Google Reader), hoping that the now "homeless" users would flock to Google+.
I don't know why they thought that this kind of bullshit would work on "techies" (the core audience of Google Reader) - that just made them wake up and realize that Google's "Don't be Evil" motto was a sham...
It was really strange and I always assumed at the time that Facebook and Google had come to some agreement behind the scenes.