Mnementh on 06 June 2014
Naturally every supported platform, feature and whatever adds effort. But if you rely on a good framework that is available for all three and don't do anything extraordinary, the effort can be minimal. Only testing it and here and there adjust some things. Such frameworks exists, Unity for example.
And for consoles you have to purchase a devkit. This is often very expensive. Probably the Kickstarters add these costs to their calculation and tehrefore make it a stretch goal.
