And what did we write? Programs to display information on the screen and let you edit it. Programs to make documents look pretty. Programs to track expenses and income. Programs to schedule appointments and events. Programs to manage contact information for other people. Programs for creating art. Programs to send and receive e-mail.
So for all this time, we've been rewriting and re-rewriting the same programs over and over again, in new languages, on new operating systems, with new GUI bells and whistles. But basically the same stuff.