Interesting idea, but built on a false premise. Jobs aren't necessarily unpleasant. You could find yourself in the position of enjoying something most people don't, like programming, or being better than every one else at something that many people enjoy, like golf.
In both cases you can get paid to do something you enjoy, and no matter how much fun you have, your boss can't pay someone else to do it because either there aren't that many other people who can do it, or there aren't many who can do it as well as you.
Indeed. Scott Adams is one of the most frustrating bloggers I know - he frequently makes sound points, but far too often you're blinded by a glaring error he makes in the first sentence or two to ever see them.
Skip the first paragraph, and the rest of this post is reasonably well argued.
Agreed, my job is quite fun but it requires specialized knowledge that produces economic benefit for my employer so they make more money by paying me than they would if they didn't. I am by no means unique -- many people are in this position because they picked a career in what they love to do not what they thought they could make a living in.
By creating a symbiotic economic relationship our companies get the stability they need in the jobs for it to be productive. The "people would be paying to do this" argument isn't true if they perceive they could be sharing in the economic benefit to the company.
Sports stars are a cherry-picked counter example to Adams' argument. Would LeBron play basketball for a mere $100K/year? You bet -- if that was his only option. It is that every team would like him to have lots of fun in its uniform that drives up his salary.
It's one counter example of many, though (indeed you neglected a second in the original comment). Most people don't enjoy their jobs, but many do, and in a huge variety of fields. People that aren't happy shouldn't be told that there is no other way, as Adams suggests.
In a similar fashion, many highly talented individuals would remain in the same industry for less pay (e.g. many highly-paid programmers). Because their skills are in demand, they can work in a satisfying ("fun") career and still be amply compensated, similar to LeBron. In fact, there is much more going on here than mere compensation: individuals doing creative work do better when they are happier. Hence, it is often in an employer's long-term interest to create an environment in which their employees are happy.
In both cases you can get paid to do something you enjoy, and no matter how much fun you have, your boss can't pay someone else to do it because either there aren't that many other people who can do it, or there aren't many who can do it as well as you.