First, please only post once. Extra posts push other threads to the bottom, making it hard for us to keep up.
There are many possible reasons (here are some I thought of off the top of my head):
1) Very few people copy on the fly.
2) Macs are expensive enough, adding another drive adds more to the initial price.
3) Until quite recently Macs couldn't write any CDs, so give them time. Soon Mac users will see a use for copying a CD and this may very well be included.
4) To keep the look clean and simple. A computer with extra drives that the vast majority don't need isn't a clean and simple computer.
5) Maybe Apple wants its customers to follow the law.
6) No one needs to copy on the fly, just copy it to your HD. Sure it takes 1 more step, but it isn't hard at all.