Why is it that these robot cleaners are so expensive? It's a plastic housing, a filter bag and an underpowered pump on wheels. All in all, a 500 dollar unit shouldn't cost more than 50 to make, and that's on the very generous end. Not to mention, all these things are made in China where labor is cheap. My better half is Chinese so I've had her look in the Chinese Amazon (taobao.com) for any alternatives, but there aren't any. There are however lots of options for filtration and pumps. Just no bots... what gives?