It is true that the less distance the steam has to travel, the better the steam output. However, if you properly insulate the pipes, less cooling occurs and the "ideal" distance increases.
Keep in mind that this equipment is designed to perform effectively while taking into account typical installation location options. This is why leading steam generators can be installed up to a distance of 25' away in most cases, and up to 50' with a ThermaSol unit. Read more about Steam Generator Location