I'm also not sure it's important that laundry and dishes get done at the exact same time - if it is, you should probably do 1 of those tasks yourself - especially since a robot would be able to stuff at night, etc, giving it more time to complete tasks
Also, GP mentions stairs, and adding wheel support to that. So not only do you want a half dozen robits rolling around your home, you'll also need to remodel your home to support it.
Or, of course, we could develop bipedal robots, which seems to have little downside as compared to wheeled robots.