I was wondering, there's something that keeps me asking myself in Star Wars and other SF universes.

Many S-F universe use "vintage" or "crappy" or "old-fashioned" designs for robots. Like C3PO & R2 units in Star Wars or Fallout or even in the Asimov's Cycle of Robots. Non-humanoid robots are described or look like big rolling trash bins.

Is there a reason why we could think it'll be like this ? Is there any rational reason (like economic reason ? Development of recycling ?)