Not sure what you all are doing to your batteries, I have an original Galaxy S that still holds charge and lasts most of the day under normal usage
I've never had a battery need to be replaced because it lost charge, and I'm on my 6th or so smartphone
maybe your switching phones so often you dont notice it? I encourage you to google "battery swelling" and you will see that I am not alone. This is pretty common, and certainly was not resolved before smartphones became "popular". My current phone, Galaxy S2 (sprint) had the same issue, and required a new battery. You will find TONS of posts of people on XDA with the same problem. Just b/c it hasnt happened to you, doesnt mean that it doesnt happen to others.
here's an iphone 3gs that was posted on reddit.