mtgox makes much more than satoshidice, basically gox makes 1% of the monthly volume, the volume is usually at least 1M BTC per month, some times more than that,
I've seen several 2M months. so gox makes at least 10k BTC per month. satoshidice makes about 2k-3k BTC per month and they depend on luck, they almost went bankrupt at the start, and had to raise house edge significantly. mtgox has two employee though, also they pay for pretty good hosting.
1% of 1mn monthly volume is like 10k. Discounting their discounts, their expenses and so forth, MtGox is roughly in the ballpark of S.DICE.