People keep thinking up new things to do with computers, and hardware keeps evolving to let you do things you couldn't do before.
It's hard to know where to begin, but let's take watching TV as an example.
In October 1965, if you wanted to watch "I Dream of Jeannie", you had to turn on the right station, at the right time. There were no other options: you couldn't record it or buy it or anything. And if you missed it, well, too bad. Maybe in a few years, they'd syndicate it and (if you were lucky) you could catch the show you missed sometime in 1970.
Oh, and in 1965, nobody had a computer except corporations and universities, they were usually at least as big as a small car, and involving a computer in TV playback was purely a sci-fi notion.
By 1996, you could buy "I Dream of Jeannie" episodes on VHS, which you could then play on a VHS player that might have an embedded CPU, and a CRT TV which might also have an embedded CPU, which of course somebody had to program. There were devices you could use to capture the video output from your VHS into your computer, but the consumer-level hardware horsepower back then was so low, you could suck down a huge chunk of a state-of-the-art hard drive with one episode, and then you could only play it back in a little teeny window on your screen.
In 2006, they started releasing "I Dream of Jeannie" episodes on DVD. When you played them back, your DVD player and flat-screen TV both required an embedded CPU, both of which somebody had to program. Or, of course, you could play the DVD on your computer, which somebody had to program to do it.
Shortly after the DVD releases, people started ripping the DVDs using DVD-ripping software that somebody had to program. And then they edited the rips into clips (using non-linear video editing software that somebody had to program), and used their browsers (which somebody had to program) to upload their videos to YouTube (which somebody had to program) for other people to view in video playback browser plug-ins (which somebody had to program).
Now, you don't even have to rip the DVDs! You can use iTunes (which somebody had to program) and go to the iTunes Store (which somebody had to program) and purchase and download 140 different episodes of "I Dream of Jeannie", which you can play back using software on your computer (which somebody had to program)
While I haven't checked this, I strongly suspect you could also take those iTunes versions of "I Dream of Jeannie" and play them on your iPhone or iPod Touch, which, of course... somebody had to program.
And I have absolutely no idea where "I Dream of Jeannie" is going to turn up next. Maybe on my wristwatch, or on some kind of wearable fabric, or projected onto the lenses of my glasses. But wherever it turns up, somebody will have to program it.
Office apps? Meh. I'd be perfectly happy still using Word 5.1 from the early 90s.
But everything else? I've been programming for 40 years now, and I expect the market for programming work to just keep growing and growing.