It's definitely way more barren on G+ than Facebook, but I think that part of this is because on G+, users are more likely to make posts that can only be seen by a small subset of the total number of users in their circles. On Facebook, most users still make posts visible to everyone on their friends list. I personally have a "close friends" circle of about 15 people and we typically just share content with each other; at the same time I'm seeing posts from people outside of this circle talking no one ever posts to G+.

Although G+ still has way fewer posts than Facebook, I suspect that it would need a much higher post rate than Facebook to appear as "active" to users.