Coca Cola bottles?? What an amazingly absurd analogy. Do you buy Coke bottles, empty? No. You buy them full and then empty them--the complete opposite of iPhone memory. Do you have to upgrade Coke bottles, and are prevented from doing so if they are merely half-empty? No.
Most people know car analogies suck. But the "Coke Bottle" is a new low.
I assume you have never encountered someone with a 16GB iPhone who dared to use it, and now can't even update to the latest iOS due to not having a enough room (enough room being just about empty). What is really "totally stupid" is Apple selling a device with such limited memory, at such a high price, and no way to back it up with Apple's services without paying even more to add to the woefully inadequate included iCloud storage. The service that has had 5 GB storage for the last half decade.
Mike