To many people it seems obvious: mathematicians should determine the math curriculum. After all, they're the ones who really understand the subject. Part of the reason for a backlash against "reform math" in the 1990s and early 2000s was the complaint that the reformers were math educators, not "real" mathematicians. They might be undercutting important topics because they didn't truly understand where all this math was heading.
But mathematicians are a rarefied breed. Outside of higher education, the number of jobs for mathematicians in the US is approximately 2900. In ten years the number is expected to be approximately 3600. That's a large percentage growth, but a small absolute number. Even when you throw in jobs opening in higher education, there are not enough to accommodate the number of mathematics PhD's being produced. There just aren't that many professional mathematician slots - and certainly not pure research mathematician slots - for students to grow up and fill.
On the other hand, there are hundreds of thousands of new jobs appearing for computer programmers, modelers, economists, accountants, businessmen, actuaries, engineers, statisticians, and people who use sophisticated mathematics to understand fundamental physics, how the genome is organized, potential damage from earthquakes, the workings of the derivatives market, or the geometry of antiviral drugs. That is, there are plenty of positions for people who graduate with strong mathematical understanding and the ability to apply it well.
When it comes to deciding what math is really important for people to know, perhaps the viewpoint of those who use advanced mathematics to accomplish practical goals is as important of those who love and study math only for its intrinsic beauty. By all means, let the mathematicians weigh in about what our children should learn - but include the applied mathematicians. And include practical mathematics. Here's an article by a friend of mine arguing about what that practical mathematics might look like.