The reason they don't is because most people want it to taste better and by adding sugar it tastes better. At least for most people who are used to eating a lot of stuff with added sugar.

One thing I have noticed though. There are LOTS of more widely varied choices for specific diets today than there were five years ago. Or at least more of the stuff stocked on grocery stores (instead of having to be specialty ordered). So that tells me there are getting to be a lot more people listening to alternative messages when it comes to health than what they are getting from the main stream view.

If the demand is there, retailers are not stupid. They will stock the stuff that leaves their shelves and rings the cash register.