Beginning skaters, whether adults or kids, start out by learning the beginning techniques of basic skating, and then as they move up in skill level they may specialize in one or more specific disciplines and develop the special skills related to that discipline, but they still need to keep improving their basic skating.
There are many thousands of figure skaters who test and compete. For female singles skaters at least, there are thousands of skaters in the US at some specific age and skill levels. To make the competitions meaningful, the events are divided according to minimum skill level of basic skating, as measured by MITF tests. Age and jump limits break things down further but are secondary to the basic skating.