But, more than ever, our kids will have to “invent” a job. (Fortunately, in today’s world, that’s easier and cheaper than ever before.)Well, quite clearly, college isn't cheaper than ever before. Quite the opposite. Even if, recognizing that your skills have become a bit rusty, you're inclined to go back.
I expect that Friedman is referencing the growing availability of online courses, free and paid, on a wide range of subjects. If you can put together an appropriate collection of such courses, you can approximate what you might learn in certain more expensive, formal educational programs. The first problem with that is curation - you generally won't know if a course is any good or how much you'll learn until you complete the course. The same is true to a degree with college courses, but the college has an incentive to curate the content and to try to ensure that courses are of reasonable quality. Similarly, colleges put together curricula to help students pick "majors" and "minors" and, ideally, take an appropriate set of courses to obtain an appropriate level of knowledge to justify being granted a degree. When you're putting together your own set of courses on the Internet, it can be difficult to know where that process begins and ends. If you are acting out of mere personal interest, sure, it's cheap and easy. If you're trying to teach yourself cutting edge job skills in your spare time, it's not easy and (assuming the material is available online) isn't necessarily cheap.
I have seen interesting programs that promise, somewhat convincingly, to take people from the beginner level to "competent and employable" in a block of time comparable to a college semester. For example, this program to teach Ruby on Rails. I think colleges should do a lot more to create and implement that type of program. But such a program is neither cheap nor easy. Sure, you can quit your job and with some decent guidance and luck in finding good resources, as well as a lot of motivation and sufficient aptitude, achieve reasonable mastery of Ruby on Rails in, say, twelve weeks. But... that's a luxury few people have.
Perhaps Friedman is thinking back to the days when he typed his columns and learned to use a word processor, but if we're serious about "inventing" jobs through a demonstration of skill sets and achievements not broadly shared by a larger pool of job applicants, for most workers I think things are getting harder. Not only are skills of that type increasingly complex, they become obsolete much more quickly than the important skills of the past. Picking the right skills to master, finding the time, finding the resources, and keeping current or moving on to the next thing? Easy? Come on.