Whether it looks like a ghost town depends on how many people you are following, and which communities you're a member of. And whether you've configured those communities to actually show all of their content in your stream, which is something you have to do manually for every community you're in. So that's a pain.
Google has been trying to hard to chase people out of Google+, but people are still holding on, because there isn't really any good alternative. It's a shame to see Google undermining their own platform like this, though.
Also, "all the devs" in Google+'s case, primarily means "all the Googlers" plus a variety of people who dev primarily on Google platforms and hence want to follow all those Googlers.
And like, for that the name would actually make somewhat sense.
It could have been fantastic, but Google seems determined to kill it. Lately I've seen very enthusiastic early fans leave Google+ and just submit to the horror that is Facebook, because at least that's predictable.
* IRC Channels
* Twitter (search by profile contents and/or hashtags)
* Mastodon? Still a bit unproven, but the atmosphere there resembles the 90s web.