decide. That decision was made a long time ago. We don't know exactly why.

If you run a movie theater, or McDonalds and are already established with one type of drink, why would you take the time and effort to change without an established demand? You don't start or change a business without creating a business case looking at the risks and demand or potential demand.
If the actual measurable demand is ~5% (As currently indicated in this highly scientific and universally accurate poll)... it is likely not worth the cost to change.
The key is, until recently, and I would guess with the help of social media and improved mechanisms to help students share their concerns, the demand has increased to the point it makes business sense to sell caffeinated drinks.
I think for most students, it doesn't matter one way or the other. They just buy what is there. The few who do care might make a lot of noise, but it is not smart business to make decisions based on noise alone. You gotta dig down into the numbers. It is quite clear that the numbers say, there was really no significant or notable demand for a change until recently. That is consistent with what I saw at BYU and consistent with what people are expressing in this poll.