There is a widely-held, and incorrect, assumption that we as people do not have the time nor the capacity to be very good at many things. I constantly hear statements like "if you want to hone your craft, you really need to make that your singular focus." Nonsense. If we are curious and passionate learners, open to new experiences, and diligent in our studies (even long after our formal education is over), then it is entirely possible to be very good in many different areas.
The paradigm is shifting. In the work world we are being asked to do more with less. And if that is to be expected and accepted, then we must also give up these debates of generalist versus specialist, breadth versus depth. We will have to develop high level skills in a number of areas in order to perform well in the new economy that will emerge after this current downturn. The idea of the "T" is no longer valid (knowing a little about a lot, and a lot about a little.) We will have to get to work on building a rectangle (knowing a lot about a lot, period.)
Look at historical figures like Benjamin Franklin and Thomas Jefferson and Albert Einstein. They were considered "Renaissance characters" of their times. They had a variety of interests and far-ranging expertise. Really, they were just life-long students who didn't accept the adage that they could only excel in a single field. They had the drive to let their curiosity be their guide, and we would do well to follow their lead - now more than ever.