As a programmer, I can make my programs do whatever I please. If I want to autosave all of my documents, I can write an Emacs script to save after every hundred

As a programmer, I can make my programs do whatever I please. If I want to autosave all of my documents, I can write an Emacs script to save after every hundred keypresses. If I want greater security, I can write a tool to encrypt my files and network traffic, and a firewall to prevent unwanted connections. If I want to sync my files over the net, I can write a dropbox-clone. If I want to get better battery life, I can set my disk to spin down, reduce my screen brightness, or disable wireless. I am also more likely to know about existing versions of these specialized tools, because it's me and my friends who build them. But as an "iPad user", I don't know any of that. If the feature isn't included in the OS, "turtles all the way down" and enabled by default, then I will never even know that such a thing is possible (and even if I did, wouldn't know how to get it). So it's really exactly for the non-expert users that OS development is so important. Everyone else (and by that I mean the minority), is informed enough to figure these things out no matter what OS you give them.