It's extremely difficult to determine this type of data. Many of these companies hide this information from their readers.
For example, I remember when Everquest stopped showing the live players on each server because they were afraid of "giving proprietary information to the competition."
It's also very easy for them to fake the data if not externally audited. This is a tough task for journalists.
Agreed. Imagine the fallout if a journalist managed to expose games that are using this kind of thing. It'd be a glorious shitstorm of denial and backpedaling.