I thought I had already cleared up the MMO vs. Gold subscription fee confusions
The Fees are completely exclusive of each other. Meaning you can have a MMO subscription without a Gold subscription. Also meaning your Gold subsciption doesn't contribute to the MMO games
Why you ask?
Simple... the Servers
MMO games require massive dedicated servers. Most of the time these servers are not run by MS but the company that published the game. Ms on the other hand runs the XBL servers. So how exactly would money you sent to MS make it into the hands of a MMO game publisher? It wouldn't, and thats why the fees are exclusive.
This doesn't necessarily mean that all MMO games will have subsciption fees. They very well could be hosted right on the XBL servers meaning that you could play online with a Gold subsciption. more often than not it will be separate simply because of the bandwith MMOs require over a reguar game.
Having owned and operated several servers of my own both game and websites. IMO the $10 a month they charge for MMO games is a rip off while the XBL subscription fee is a bargain if you actually use it frequently. Ultimately it comes down to this: Things are only worth as much as someone is willing to pay for it. If most gamers weren't willing to pay $10 a month subscription fee they they would have to lower there prices... publishers will always squeeze as much out of you as they can, that's just what they do; if you don't like it then speak up with your wallet.