How is it greed? They are offering something free. Just not for everyone. That's like Starbucks offering a free drink for people with a gift card who register for an account on their site and you, who didn't meet those requirements, are moaning about it. Nothing about the hardware justifies this, but that is irrelevant.
Another good example is when you buy a Mac, but over a month later, a new version of iLife is out. Only people who bought that Mac at that time or later gets a free upgrade and you don't. You have the same hardware right? Even more outrageous then, since the 3GS and 4 are totally different hardware.