When you go to the car mechanic to get your car fixed, you've got some idea of what it will cost. It may bot be a good one, but its an estimate that you've got in your head. Maybe a $300 part and two hours labor at $100/hour or whatever insane rate they charge, so $400 to $600.
Today's world is becoming more and more with someone working with a programmer.
It may be as programmer themselves (and anyone who been on the searching for a good applicant side of an interview knows its hard to find good programmers) - we need more programmers more than we need another person working at Mc Donald's. Certainly, not everyone can be a professional programmer, but I'm sure there's a lot falling through the cracks of society never realizing that they want to be a professional programmer (or for that matter, can).
It may also be someone hiring someone to do a job. A small business person hiring someone to write a front end to a database for a CRM, or website, or whatever. Look on eLance some time and glance at the estimates that people have - "I want a Facebook clone in 2 weeks for $500." Try not to laugh too hard. They are out there asking for such absurdities. Thats almost like going to the mechanic and expecting that part to cost $0.50 and the person to work at $5/h... um, no.
By having an idea of what can be done, and an inkling of an idea we get clients and managers that aren't going to want *everything* done today. Well, they will still want it, but when you tell them the actual price and timeline, they'll maybe not think that we're trying to rip them off (while we sit back and click on webcomics and write our own Facebook clone all day... or at least thats what they think we do).
There's also the aspect of people becoming a bit more literate in computing itself. They'll hopefully have an idea of what a computer can and can't do. No, cookies aren't stealing your information - the key logger that you installed with that game you downloaded is. The cloud is not affected by the weather. So on and so forth...
Looking at the number of people who have interactions with computers today compared to 20 years ago, I suspect that more people work with computers in one way shape or form than their own oven... unless its a microwave oven, with an embedded... oh yea. Computer literacy and basic ability to write a program is almost as important as regular literacy and being able to write an essay. It doesn't mean everyone will do it every day, but its becoming basic life skills in today's world.