I can play a match in Age of Empires II for ten hours straight against my friends without getting bored.
Still I think the OP might be on to something here, because I've never enjoyed Starcraft. I think the key is that many people (like me) enjoy the feeling of creating things. We enjoy games where a single peasent can create something that will become an empire... And as the sadists we are, we also enjoy crushing our friends' empires.
But there are other things as well. I love chess, card games and monopoly. But I've always hated the computer versions of these games. I also happen to enjoy books, but I would never pay to read a book on my computer. I love storytelling around the bonfire, but when I go to the movies I expect to actually see the action and I would be very disappointed if the entire movie consisted of a guy sitting on a rock telling a story.
The difference between playing chess with a friend and playing chess against the computer, is that you can't socialize with the computer. You can't discuss the game with the computer afterwards. When you win, that's it. The fun is over. Therefore, computer games, at least single player games, must add something else to the equation to actually be fun. Things that you can show your friends and brag about. It may be a magical sword that's almost impossible to get, a huge theme park or a powerful empire in Civilization.
The goal with every Civ game should therefore be to make the player feel like the leader of an empire, not a participant in a board game against the computer. And no, I'm not the sandbox guy that want to build my cities in peace and watch them grow. I'm a math nerd, I want the numbers, I want the odds, I want to do the risk calculations. It's just that playing Civ V doesn't offer me anything more than I get from playing a game of cards with my friends.