Interesting information.
Yes, here in Bolivia (formerly called "Alto Perú"), they drink a lot of chicha, too. In the highlands, usually fermented (alcoholic); in the lowlands, often not. And yes, it is often prepared by chewing.
You can buy coca leaves at the local market (commonly called "cancha"). As I said previously, use or possession of E.Coca leaves isn't illegal in Bolivia, and it is not usually considered a drug. I, and my family, drink "trimate" (tea from a mixture of herbs that contains perhaps 10% coca), just like any other tea (mint, hibiscus, apple tea, black tea, etc.), and I don't notice any weird effect, such as you would expect from a drug.
I find the coca-chewing somewhat disgusting (bad smell, people spit on the ground), but I find it doubtful to call the un-refined leaves a drug, even if chewed all day. At least, it would be much less strong than the refined substance. I do find it a dangerous habit, as I pointed out earlier.
BTW, a common saying goes "coca isn't cocaine". While this maybe technically correct, I don't completely agree. Not because of the (I believe, insignificant) amount of cocaine in the raw coca leaves, but because 80% or something of coca actually is used to produce the cocaine.
I definitely do consider alcohol a drug; and chicha (the fermented version) is smellier than many other beverages.
Hilmar.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)