5. Hypercard. 1987, 32 years old.
does this belong on the list, given that it’s no longer maintained?
well, there are still people who still use hypercard, either in a physical old mac or via mac emulators. they use hypercard to get useful work done. including bill atkinson. there are many imitators and clones, but somehow none come close to the approachability and and functionality tradoffs of the original. there are practical benefits to software that never changes.