So I read this WaPost article about the Google+ debacle because I wanted to find out what was going on, having seen - as is so often the case for me and news events - secondary material about the fallout without having seen any primary exposition outlining the facts.
And it also said, "For a time, Google made it so convenient to create a Google+ profile that you basically couldn’t make a new Gmail account without also signing up for the company’s social platform. Only those who were paying close attention could really avoid it. To this day, you might have a Google+ profile of your own and not even realize it."
I kind of doubted I had one. Google+ was launched in 2011, and I've had a Gmail address - which I use as a secondary address for when there's problems with my primary address - since at least 2010, which is the date of the oldest entry in my inbox, and my recollection is that I got it while Gmail was still in beta, which it came out of in 2009, according to the Wikipedia article about it. So how could I sign up for a service that didn't exist yet when I was signing up for the other service?
However, there was a link to another article explaining how to find if you have Google+ and how to delete it if you do. And to my surprise, I did. I don't know how this happened. So I followed the deletion instructions - which I would never have done if this hadn't been a trusted source, because I would have feared deleting my Gmail as well - and it's gone. I'd never have realized its presence without this, which is why I'm passing all this on.
But this does suggest why Google+ never succeeded as a social media platform. Nobody's going to use a service they don't realize they have. How stupid do you have to be to sign up your users for a new service and then not tell them you've done so? As stupid as Google, apparently.