I too have no need to invest in a new iPad and I am using the most current version of iOS that is compatible with my device. iOS 7 was not designed for use on this model. Over the past couple years, some applications just stopped working, but most work just fine. As already mentioned, incompatible apps/downloads simply won't show up in your upgrade list. No worries, continue using the device as is and don't worry about what might happen.
I have an iPad 1 that works fine for me, I really don't see the need to upgrade at this point.
My Question is - with all the App updates to conform to iOS 7 - should I update the ones that are shown for me to update on my iPad 1 ?
I have an iPhone 5 & my wife has a 4S which I will update but my concern is with my iPad 1.
Thanks in advance for your advice & assistance.