1. Most iOS Gamers (meaning people for whom iOS is the primary/only gaming platform) aren't really Gamers. And I don't mean that as an elitist thing, they just aren't. Gaming isn't a hobby for them, it's an extra distraction while they poop or wait for a bus. As a result, they aren't really willing to drop money for that aspect of iOS.
2. As others have pointed out, Apple has only themselves to blame for fostering a consumer culture where $5 is a huge amount. Why buy a game for $5 when you can buy a game for 99 cents? And no, saying that the $5 (or $25) is likely a bigger, better game doesn't count - see the previous paragraph, these people aren't gamers. They aren't looking for deep, rich gaming experiences. They are looking for occasional timewasters.
3. iOS is a shitty platform for gaming. The touchscreen interface only works for a specific range of games, everything else needs contrived and lackluster control schemes. Sure, there are peripherals that allow for controller functionality, but that diminishes the practicality argument, which is one of the biggest selling points of iOS gaming.
4. All this simply means that there's not much of audience for major titles on the iOS. You are looking for people who care enough about gaming that they are willing to pay for a more robust experience, want those experiences on a mobile device (for whatever reason), but at the same time don't want to get a dedicated mobile gaming device. I'm not saying those people don't exist, but they aren't a huge market...
2. As others have pointed out, Apple has only themselves to blame for fostering a consumer culture where $5 is a huge amount. Why buy a game for $5 when you can buy a game for 99 cents? And no, saying that the $5 (or $25) is likely a bigger, better game doesn't count - see the previous paragraph, these people aren't gamers. They aren't looking for deep, rich gaming experiences. They are looking for occasional timewasters.
3. iOS is a shitty platform for gaming. The touchscreen interface only works for a specific range of games, everything else needs contrived and lackluster control schemes. Sure, there are peripherals that allow for controller functionality, but that diminishes the practicality argument, which is one of the biggest selling points of iOS gaming.
4. All this simply means that there's not much of audience for major titles on the iOS. You are looking for people who care enough about gaming that they are willing to pay for a more robust experience, want those experiences on a mobile device (for whatever reason), but at the same time don't want to get a dedicated mobile gaming device. I'm not saying those people don't exist, but they aren't a huge market...