It's not that long ago. GIF certainly predates it. I think ZIP does as well, and probably EPS, just to name a few for scale. None of these does exactly what PS

It's not that long ago. GIF certainly predates it. I think ZIP does as well, and probably EPS, just to name a few for scale. None of these does exactly what PSD does of course, so it's impossible to compare them. A better example is perhaps TeX, which predates it by far, has been extended a lot during the years, and can still render both original documents as well as modern ones.