Because it is made of rubber! Also, the first person who made Barbie dolls was a woman in her thirties. Because she had no children and wanted to have a lovely daughter, she made a lovely doll with a sweet smile, which was only half the size of an arm, made of rubber, and asked the most exquisite tailor she hired to make many beautiful clothes for the doll. She also hung them in the closet and stayed with the Barbie every night. No matter what Barbie doll is, it is based on the doll made by that lady, which is of course very expensive. Also, Barbie's clothes, shoes, hats and other clothes are all made by exquisite tailors. Also, Barbie's arms and knees can be moved, such as knees and arms can be bent, and the joint between shoulders and arms can be extended outwards, which is of course expensive!