You have made many many errors in your comment. Many of them are integral to propping up you misguiding conclusion. I would like to correct your errors.
Your first, and most egregious, error was to say that Apple has remove apps or "upgraded" them to versions that can't run. This is an outright lie. When I get an app that can't run on iOS 6, Apple simply informs me of this and gives me the latest version of the app that supports iOS 6. When an app gets an update that doesn't support iOS 6, the app is not updated. You said that Apple prevents developers from creating apps that run on iOS 6. This is not true. You can go on the App Store and check for yourself. Many apps still support iOS 6.
You also said that iPod touch 4 was being sold last year. While this is true, it leaves the wrong impression. iPod touch 4 was being sold last year, but iPod touch 5 has been on the market since 2012. Anyone who bought an iPod touch 4 last year knew they were buying an old device. Speaking of old, you should know that iPod touch 4 was released in 2010. That's 4 years ago. It was first sold running iOS 4, and was updated to run 3 new operating systems. That puts your comment about "being sold last year" in perspective.
3rd, you said that your PC from 2007 is upgradable and still runs well. That is good for you, but it's relevance is questionable. Computers will always be more upgradable than pocket computers. Many Macs from long before 2007 still run very well.
4th, you said that iPod touch 4 is still "perfectly good" and that it would be ridiculous to say that it can't run new software. Well, while the iPod touch 4 was good for its time, but it only runs 256MB of RAM. The iPod touch 5 runs 512 MB, a great improvement. Even the iPod touch 5 has some trouble running the the latest software (iOS 8) up to speed.
While I agree that it is disappointing that the iPod touch 4 can't run iOS 7, it is by no means a conspiracy of planned obselescance. I know you will probably write me off as some Apple fanboy or apologist, but you are an even more doggedly idiological creature. You are an Apple hater, and before you write me off for being a fanboy, you should get your facts straight.