I was interested in google+, but it wasn't worth the risk. This was also the point where I stopped playing with new Google stuff, and started logging in only for email, and logging out.
Now there is no way for Google to know all this, so I assume I got classified under the 'no big deal' group in your analysis.
If you didn't have contact with either marginalised groups who as a matter of survival didn't use their real name or ancient extremely online people who for the entirety of their internet experience had been known as a handle it wouldn't have crossed your radar.
But it was a huge thing.
Thing is, that small group is your grassroots, influencer base without which you fail to thrive. G+ never got beyond the starter 'tech nerds' blogger type adoption and out into mainstream headspace.
You don't have to bow to that crowd to succeed, but at the very least you have to avoid annoying them away from your offering.