Because the market is much, much smaller. I don't know what percentage of iPhone users actually jailbreak their phones, but looking at the iPhone users I know,

Because the market is much, much smaller. I don't know what percentage of iPhone users actually jailbreak their phones, but looking at the iPhone users I know, I can only think of one person that jailbreaks. It might not be worth the effort of actually making a different version just for people who jailbreak. If app developers really did embrace this, that might drive more people to jailbreak, but I highly doubt your average Joe going through the process of jailbreaking, even if it isn't particularly hard. On top of that, there might be fears of piracy. I don't know how valid it would be, but targeting users who jailbreak is also targeting the only people that pirate since you have to have a jailbroken phone to pirate.