I don't think that's what they're supposed to be but I do agree that in many cases, especially when it comes to addictive goods/services, that's basically what it amounts to.
But there are definitely cases where businesses don't try to sell you stuff you don't need (however subjective that determination can be) and those are places that I tend to get back to.
I'm not a sales man but I'm certified in SPIN selling. It is used heavily by Apple. What it involves is either exposing, overstating, or even creating a need, building up on the imagination of the user (how wonderful it would be if I...), and then finally sell the product and close the deal.
My point is though, in the grand sceme of things sales are about selling, regardless of the mean. It is not all evil by the way! Sometime people really need the product that's being sold to them, or at least, it will make their life better.
Again, I'm not a salesman, I don't have a horse in this race, but I just wanted to clarify.
There are unethical ways to make money and this is one of them - the amount of bad publicity Apple is getting and the fact that it's refunding many people, me included, suggests that this is is not a business model a reputable company should use. Also, I expect the money is a tiny part of its profits.
Let's put it this way; Apple constantly does cost benefit analysis of all its business operations - just like any other fiscally responsible company - if In App purchase cost (reputation, money, time) exceeds it's benefit, it gets axed.
It didn't get axed yet, so this means it is a beneficial program. Maybe it will get axed soon, but it seems at this point regardless of millions of dollars of settlements (and employee time used), it is still profitable.