I think the failure of Google + is typical of how Google is. They do not take a long breath and only seek absolute profit, anything less than this needs to be killed.
At first, Google+ was refreshing and superior to Facebook. Faster, harder to spam or better advertising, and almost all features worked the best. Photos looked better. Communities and circles worked very well, especially if you were interested in such specializations as photography, technology and the like.
For me, the promise of a social network is not Aunt Truus who went to the zoo or has new garden chairs. The promise is to get in touch with complete strangers who share your hobby or passion. Google+ was good at it.
Despite all the jokes and jokes, at its peak were hundreds of millions of users, many of them quite active. And at this very moment of perseverance, it is typically Google throw in the towel. A few hundred million find Google a failure. Not taking Facebook out of the throne within 2 years is a failure.
Then they did nothing else and let bleed to death. No features, no fixes and spammers have lots of space. It took many years, but I was sure it was coming to an end.
I had not worn it for years, but it was quite active at first. The lesson learned here is never to put more energy into Google services because there is no more reliable business.