There are a number of ways to become knowledgeable about and skilled at the craft. Many chefs have a college degree or at least some college experience, while others go straight to a culinary arts school, or participate in a training program at some kind of culinary institute.
Some chefs get their start after receiving in-house instruction while working in a non-cooking capacity for a hotel or restaurant. Others pick up their cooking skills in the military (although it may take a period of adjustment to realize you don't need to keep cooking everything on a Sterno stove).
Remember, just because you can walk into your kitchen and whip up something gourmet in a matter of minutes doesn't mean that there isn't a lot to becoming a professional at this stuff. There's a reason there are so many cooking shows: there's a lot to learn.
There are a zillion different styles of cuisine (barbecue, vegan, French, Italian, German, Greek, etc.), and just as many cooking methods. There's even a lot of science involved. What effect will this ingredient have on that one? What can I add to make this dish more savory, more subtle, or more robust?
At the end of the day, getting this job takes a fine mixture of skill and experience. And much like French pastry, there are many recipes for success.