When we eat somewhere western, like McDonalds or KFC, I really start to wonder who started giving out 'child sized' drinks to all the adults in Indonesia. There's no free refills, and honestly, the largest drink available at KFC (after you upsize) is still smaller than 'regular' in the states. McDonalds and Burger King are better, but still, the largest 'upsize' is maybe a regular sized drink in the states.
It probably turns out that Indonesians probably drink the normal serving size? Or perhaps it is a money thing? The larger bottle on the left is $.34 and the new tee-tiny bottle they have just come out with on the right is $.23. I really think that cost may have more to do with it than anything else.
Another interesting factor here is that nicer or rarer drinks, such as Coke Zero, or A&W, only come in single serving sizes as cans, which are up to double the price of bottles. You pay for wealth here. And there is no 'economy of scale' in Indonesia (or there is, it just runs backwards)...
The idea (this was true many times in Nepal, too) is that you pay what you are able. Rich people (such as all westerners... because, after, all, your plane ticket to come to the country costs more than most people's yearly income) are more able, and have the ability to pay more.
So when you use more water, the amount for each liter of water actually increases many times.
When you increased the electricity on your house, each minute your light bulbs are on costs you a little more than everyone else.
So maybe 100 gallons of water costs someone $10.
But if you used 1000 gallons, it doesn't just cost $100, it probably costs $150.
The idea of buying in bulk to save money just doesn't compute in a society where none has that ability. And actually, interesting enough, I finally saw prepackaged cans in a cardboard box for the first time in 2 years overseas. And there were 4 cans in the box. No such thing as 12 packs.
It's a different side of the world we are living on!