I don't think this has to be the case at all. It is true that there are a lot of courses that we force students to take, especially at the high school and college levels, that won't really help them in their career choice. For example, when was the last time you needed to convert moles to something else (how many just went to google to find the formulas)?
I would agree that there should be a basic understanding, but really, most of what you need to know for daily life could be done in a month or two at most freeing up time for other subjects.
Granted, I have no idea how this would play out in a normal high school setting. But as I see it, we aren't exactly doing the greatest job teaching skills that are needed to compete in today's world and perhaps more choice/customization of a learning curriculum would produce more viable people for the workforce.