Robots do not build themselves (with the exception of a very few simple ones that were built by human researchers who are very clever, and worked very hard, and still managed to build only very rudimentary sorts of robots).
Because it takes so much work to build a robot, the builders have to have persistent focus. Usually that is driven by intense, focused interest. Mike Sullivan, the main robot-builder in the new film The Meaning of Robots appears to have a quite particular focus. Here’s the trailer for the movie. WARNING: Do not watch it if you are easily offended by anything.
BONUS: To see and savor some of the kinds of mechanical bits and doodads in the film, you can, should you be in New York City, take a jaunt to the surprisingly-almost-family-friendly Museum of Sex.