Up to a point. Google+ was invite only for so long that by the time it became available to the general public no one cared anymore. When people signed in with their new accounts they couldn’t find anyone they knew, and they never came back.
Really stupid on Google’s part, because they launched at a time when people were angry with Facebook for selling private user data, and a lot of users probably would have moved to G+ if they had been able to.
Yeah, I don’t use Reddit any longer, but it was really great that there were active subs devoted to incredibly obscure topics. If you wanted to talk about something, chances were that thousands of other people did too.