First of, I am relatively new to Gazebo - I am just starting to get into it, so the issue I am experiencing could be self-inflicting.
I have attached some files to reproduce the issue.
I am using ROS Kinetic and Gazebo 7 on Ubuntu 16.04 LTS.
When I place the VLP-16 model in the vrc_driving_terrain model, suddenly Gazebo is no longer publishing anything anymore (state publisher, point cloud, clock, etc.).