Before rice cookers, in southern China rice was steamed in a clay pot, in Japan a heavy iron pot.
Japan invented the electric rice cooker in the 1950s. In the 1960s, Panasonic, then National started importing the rice cooker to Hong Kong. The agent in Hong Kong then requested some modifications to the rice cooker (a window in the lid, congee function etc) and the rice cooker then went from Hong Kong to all the overseas Chinese communities, then to China, and then global.
Japanese rice whether cooked in a electric rice cooker or traditional iron pot tastes the same. With Chinese cooking,plain rice cooked in a clay pot tastes better than plain rice cooked in a rice cooker. So the agent in Hong Kong starts doing cooking demos, and to make the rice taste better, just before the rice finished cooking, they'd open the lid and put a chinese sausage, or some salted fish on top of the rice to make it taste better. To know when to put the sausage or fish in, you have to see whether or not the water is nearly all gone, hence the requirement for the window in the lid. In the 70s you could tell what market the rice cooker was for by if it had a window in the lid or not.
The super expensive rice cookers are for the Japanese market, it's all about iron pots, induction heating, and high pressure. They only cook rice. The top ones are around £2k. The top ones for the Hong Kong/Singapore market are around £1k, they are induction, but are also multi function, they can do congees and cakes etc. Most people in HK would spend around £100 for a rice cooker. Rice cookers are now a source of national pride. China's Xiaomi company went all out to build a rice cooker better than the Japanese. They did this by poaching Toshiba's rice cooker designer. So the Xiaomi rice cooker is well rated, and quite cheap compared to the Japanese models. It works with a smart phone app, and by scanning the barcode, it can adjust the cooking time for the rice, well in China anyway.
I grew up with a National/Panasonic rice cookers, but recently the wife switched us to a Zojirushi. They're ok, they play mozart when the rice is cooked.
I don't think many people can tell the difference between rice cooked in a £20 rice cooker and a £2000 rice cooker. Think of them like watches, the cheap ones are Casios, and the expensive ones are Rolexs. They do the same job, but some people do like to spend money.