iPod touch 4 iOS 7 compatability

I don't see why the iPod touch 4 can'g get iOS 7. Apparently, the 'old' hardware isn't compatable with it. The iPod 4 is not very old and there is no reason apple should be locking a device out of the new updates considering how relitively new the iPod touch 4 is. This sounds like another excuse from apple to make people buy their new overpriced products. I am perfctly happy with my iPod 4, and I am not wasting my money on a device with a larger screen and a better camera. I've also heard that the iPod 4 doesnt have enough memory to support iOS 7. How hard would it be for apple to create a slightly smaller operating system designed to run with less memory? I do not want my device to go out of date just so apple can make more money of the iPod 5. I do like the new look of iOS 7, but that's not the main reason i want iOS 7. I have 2 BIG reasons that I want iOS 7. 1: Many aplications will soon not be compatible with iOS 6, which means I wont be able to keep my apps up to date, and I wont get as much use as I can from it. 2: More seriously, as iOS 6 goes out of date, the iPod 4 will miss out on security updates. From what i positively know, when Apple discontinues supporting an older device or software, it no longer makes available to them security updates, even when new vulnerabilities are identified. That was what really set me off. I want to know exactly why apple can't get the iOS 7 on the iPod 4 and if I don't get a good answer, they can expect to lose buisness from me and the rest of my family.