It's cutting costs, really. Future has become stingier and stingier. PC Gamer US, UK and PC Format used to have their own articles and while many writers between Gamer and Format were shared and if a writer couldn't review a game for Gamer, he could review it for Format. Result: you had two opinions and had a reason to buy both mags.
Honestly, I'm not impressed by this cost cutting. People notice as this topic shows, and when you subscribe to both mags, you feel ripped off and rightly so. For the money they save, they also lose subscribers AND less reviews are available for readers to check so the only one 'winning' is them and only by a small margin. They must be very desperate to do this - maybe PC Format sales have been so low that they had to cut costs?