Kbin seems alive and well to me. If it wasn't for this post then it would never have occurred to me it might be 'dying'.
The growth in users has slowed but not reversed, and that's no bad thing. Initial growth was always going to come in spurts (driven more by whatever the latest drama is over at Reddit) and this lull is useful for getting our communities well-established and letting @ernest keep up the great work on the development side - all of which will ensure we're in a good place to ride the next wave of migration from Reddit when it happens!