This particular kind is easy to explain an answer for - not cheap/easy/etc enough. 6 axis are quite common, and getting every more common They were always used

This particular kind is easy to explain an answer for - not cheap/easy/etc enough. 6 axis are quite common, and getting every more common They were always used, but are now like, not the price of a house in the bay area for a reasonable one. It's rare to need a lot beyond that for say, production line manufacturing for a wood processing plant. Everything is already in line, etc. They can lift and move things, spray finish, you name it. Most of the time is programming. The arms can be fast and accurate. Now, the more general kind of warehouse work, like people walking around shelving things, that's harder - you get into issues around size of motors, actuation accuracy, etc. In lots of cases it's easier to design a warehouse around robot capability than design robots around warehouse structure. Unless there are dramatic breakthroughs, you will see arms and such get used more and more at places with less money and lower margins (IE random metal/wood shop) well before full on bipedal/quadruped robots. Or you know, people will use the arms as novelties to smack the person who broke the build in the exact center of the back of their head with a precise amount of force. Both seem equally likely ;)