Yes, it's simple enough that any dad or adult for that matter can pick up and play. Categorically speaking though, it's so old there's no market for it anymore only those hardcore left are playing it because it came out a decade ago before many adults were even intrigued with video games so I think that's an unfair point.
Again, age is really hard to determine for this game because it is so old. Anyone around the age of 10 will probably not even know of its existence until Starcraft 2 is released. I also think most of your points so far are speculation but i'm trying not to assume anything. You're obviously more knowledgeable in this area of expertise but I don't feel the fact that it's not a console game does much to hinder it seeing that it plays on any computer due to the basic and rudementary graphics. If something like Ragnarok and Everquest which are both almost a decade old as well and only on PC can draw a crowd as versatile as ages 10 to 50 then so can any other pc based game.
Concerning young adults, a certain console doesn't have to be a players favorite in order to yeild results for sales. For instance, pc's are useable in many different ways than a simple console and generally a household will have more computers than console systems. Again I feel like the marketers are trying to break down these player markets too finely. Perhaps Starcraft wasn't a great example but I only mentioned it to acredit where the phrase was I stated earlier.