That will happen increasingly, because developers have to make choices about how many resources to dedicate to old vs. new devices, and whether to gimp their feature set and other advances because of the limitations of older hardware.
The limits of my iPad 1 led me to get iPad 4. I didn't need more features, but my iPad 1 had begun to show its age. I was going to keep it indefinitely and use it for movies and photos (mine is 64GBs), but I've decided to give it to a kid who can't afford any iPad, hoping that he'll get some use out of it. I just backed it up overnight and will be dropping it off today.
I've gotten my money's worth from iPad 1, and think it'll be appreciated more in his hands now.