My iPad 1 can only be updated to iOS 5 yet most apps run on iOS 7. Why can't I make the update on my iPad 1? Is this so I buy another iPad 2+? Now why would I want to buy something that will be obsolete in a few years?

You cannot make the update because later version of the iOS require more advanced hardware.

It's not obsolete as much as the first gen simply lacks the power to run the newer operating systems. IT doesn't have enough RAM. If someone managed to hack it to get iOS 6 or 7 on there they'd just have a slow, boggy and unresponsive device. (think putting windows 7 on an old laptop.

Unfortunately software moves faster than hardware. Every thing goes obsolete. I've had my ipad 2 for two and a half years now and I know it only has so much longer left to it too. Just the 'joys' of advancing technology.

Blame the app developers for not providing a IOS 5.1.1 version of their apps, not Apple. Many apps started life as websites, as long as you can reach the web you have a viable iPad.