I believe there are two most important factors in producing hit games: excellent game and excellent marketing. I’m sure there are many elements that make the hit game (such as excellent team), but it all boils down into these two items: quality and marketing. They are like the two wheels of bike: if one is missing, the bike won’t go very fast.
There are excellent games that aren’t selling well. Why is that? I believe their marketing efforts (such as market research, segmenting, proper promotion, branding) might be insufficient. Maybe they have the best game that’s ever done on this planet – but if nobody hears about the game, it won’t be a hit game. Excellent quality alone cannot guarantee massive sales. It’s like a bike with only back wheel: you won’t get anywhere where fast with it.
On the other hand, there are games that have millions dollar marketing budget and billion dollar brands behind them, but the game just won’t sell well enough. That’s simply because the game quality is missing. Again the bike with only front wheel won’t go very fast. It’s waste of (lots of) money to start high budget marketing on a game that nobody wants.
But sometimes… sometimes, some guys get it all right. That’s when Sims, Oblivions, Myst and similar AAA games are brought alive. They might not appeal to everybody, but they appear a massive amount of people. Great game, with a great marketing produces a hit: a 2-wheeled bike in great condition.
It takes two wheels to get the bike moving fast. In games that means: excellent game and excellent marketing.