I dunno about that. I remember very vividly that compared to the prior product, New Coke tasted flat, gummy and greasy, and you couldn't seem to get it cold enough; it had no bite. When we got "Classic Coke" back a couple of months later it could have been the stuff we were drinking before, but now it was hard to be sure. We regarded the Coke label with new suspicion. The New Coke debacle screwed up brand perceptions something fierce, which is one reason why (A) Coke abandoned the one-true-cola position, the "Real Thing" thing, and began generating dozens of weird variant brand extension products, and (B) I switched to Diet Pepsi.

Also, maybe glass bottles do have something to do with taste clarity and retention. I used to buy Diet Coke 16-ounce returnable bottles by the case in the early 1980s and it tasted great. Today's Diet Coke in plastic or cans tastes like water with potting soil in it.