I've been thinking about buying a Sony mirrorless camera for video but after reading so many horror stories, I've cooled off of that idea. From doing lots of research and asking questions, it seems that Sony's midrange cameras overheat after about 5-10 min of shooting video and their high-end cameras overheat after 15-20 minutes.

Why do they overheat? How is this acceptable? How do they get away with it?