From a financial standpoint, a kid with mediocre grades in high school would be far better off joining an ironworker's union (had a friend making $60K+ at age 20 with the potential to make $100K+ as a foreman) than going to Dingleberry State University just to land some run of the mill entry level business job starting at $35K while having to make payments of $500 a month for the next 30 years. Similarly, a person would be far better off skipping law school and starting off in that entry level $35K/yr insurance sales job and gaining 3 years of experience and standard bonuses in the field rather than dumping $100K+ into an education to land a job as a prosecutor starting at $40K. But if the kid would rather sell life insurance plans than dangle from a crane or would rather try cases instead of selling life insurance plans, can you really blame them?
The people who are "shocked" by the idea that not all lawyers are wealthy, successful, and/or happy are those that have failed to do their research ahead of time. From my experience at a T4 and now a T2 school, there are far more people who bought into the idea that a law degree is a big money earner than those who were fully aware of the consequences of pursuing this degree. This is why I'm a firm believer that most students who go straight from undergrad to law school are making a mistake because they are not really getting an idea as to whether an alternative career that requires no further financial investment would be desirable.
I think it's also unreasonable to assume that the small percentage of law students who do land those BigLaw jobs are going to be happy as well. You might very well be satisfied on more than a financial level with a position like this, but on the other hand...you might realize that you're balding and gaining weight at the rate of the common 65 year old, that you rarely see your kids, and that you can't get it up for your wife anymore because of the long hours and stress that accompanies such a line of work.