So now instead of a single bottle, you have a plastic bag, a straw, and a rubber band as litter all the while destroying any guarantees of not getting food borne illnesses.
I don't know about the economics or logistical feasibility of returning to the same setup, but to suggest it's not possible (while still ensuring product safety) is inaccurate.
But glass bottles are heavy, and I'm sure that makes shipping more expensive and increases CO2 emissions.