Then you lose modularity, which is a huge benefit to PC gaming? Now if you want to upgrade to the newest graphics card, you also need to get a new motherboard.

Then you lose modularity, which is a huge benefit to PC gaming? Now if you want to upgrade to the newest graphics card, you also need to get a new motherboard. Which also could mean you need a new CPU, which also could mean you need new RAM. Right now you can just switch the graphics card out for another and keep everything else the same.