They probably have a very different idea of "paid" from the companies creating the software. Even though you "bought" a piece of software, it's more accurate to say you "licensed" that software. Buying something in a box doesn't change this in the eyes of the law and companies take advantage of this.
What can be done to change this perception? If "software is eating the world" then it's hard to see where this ends. Soon you'll have ads in your car, or on home appliances.