The reason is simple,.. You'd be amazed at how many people I know that have never heard of Shrapnel Games, let alone Malfador Machinations. Virtually all their business is strictly Online and I don't recall ever seeing an ad for their games in any magazines. I have seen a few reviews of their products, but usually they are single page reviews or smaller. The review runs in for just that one month and I'm sure the sales must increase slightly when the issue comes out. But the bottom line is Shrapnel and MM have made virtually all their success due to word of mouth.
Personally I would think that shrapnel along with a few of their best selling developers could manage to scrape up enough money to place a half (or full) page ad to run for a period of a few months. Word of mouth is a very good supliment to advertizing, but not a substitute.
AT, try this test,.. next time your in a computer store ask the shopper next to you if he/she has heard of Shrapnel or Malfador Machinations.
Heck, with the savings in bandwidth since the upload forums have been down they should have saved enough money to place full page adds in 2-3 magazines.
As far as the 'other' gamming sites not having an announcement of the new SE:IV GOLD patch, write a small review and highlight the best of the new features and send it to the gamesite's admins. I'm sure they would be happy to post it for you. Cause right now it's the fans that are supporting and promoting the game the most.
I really think that Shrapnel should get more agressive in their advertizing. They have many great games, and a whold world of potential clients that don't even know they exist.
Nuf said, Cheers!