I don't think Apple would make a waterproof iPhone just yet. First of all, electronic devices and water just don't mix and it's a bad idea.
Even if you did want to, you would have to make sure without a doubt that the device would not be affected by the presence of water. Then there's the issue of how practical is it...
Does it intervene in any way with the experience of the phone thus far?
Does it require you to constantly plug the data port and headphone jack?
How do you make sure the waterproof feature will last as long as the life of the phone?
What method do you even choose to make the phone waterproof?
These are the things Apple would ask themselves and so much more before they would include any feature. If they don't believe it's the right thing to do at the moment, then they don't do it. And they've said it over and over. So what else is left? What other features could the iPhone 6 bring to the table after the 5s?
Even if you did want to, you would have to make sure without a doubt that the device would not be affected by the presence of water. Then there's the issue of how practical is it...
Does it intervene in any way with the experience of the phone thus far?
Does it require you to constantly plug the data port and headphone jack?
How do you make sure the waterproof feature will last as long as the life of the phone?
What method do you even choose to make the phone waterproof?
These are the things Apple would ask themselves and so much more before they would include any feature. If they don't believe it's the right thing to do at the moment, then they don't do it. And they've said it over and over. So what else is left? What other features could the iPhone 6 bring to the table after the 5s?