It is a licensing thing, and something you'll see a lot of with wireless cards from all manufacturers. Wireless chipset makers have moved a lot of the device functionality and control out of hardware and into firmware. The good news is that it makes it cheaper and easier to fix bugs and upgrade cards, since you need to change the firmware rather than the hardware. The downside is that it puts all sorts of things, like operating frequency and transmission power, under software control and the manufacturers are afraid that if they release it as open source code, people will do all sorts of nasty things with it. At least here in the US, the FCC would probably take a pretty dim view of this.
So the firmware is considered proprietary, and usually has pretty restrictive licensing. So rather than get into trouble, firmware isn't included. The real downside to this is that new Linux users rarely recognie that firmware is required, and because there appears to be a functional driver, they think it simply doesn't work. I'm not sure how this eventually gets resolved, but at the moment it is a real problem.