Why aren't servers full anymore?

Back in the day (like 2 years ago) you could hop on Hoggit or Blue Flag and be in almost full servers. I used to watch the GCI at work and about 90 percent of the time the servers was about 5 people away from being full. I just looked and there are 5 people on the Hoggit GAW server, and like 2 in Blue Flag. What happened?