Use wheels and buy two if you have to...the Roomba solution. Besides, why do you need to solve stairs the hardest way possible, a fully bipedal robot, before it moves past vapor?
I think the key is that none of our actual home use cases can be done with just arms. You don't need your folded clothes sitting in front of your washer and dryer, and a set of arms can't handle folding sheets.
Why not? I would love to have a set of arms that could flip the laundry from the washer to the dryer and then take it out of the dryer and fold it and put it in the basket.
I understand that particular use case sounds cool! I really do.
And then you want them to put away your dishes, and they can't, even though it's just a software update, because they're across the house. And they're BIG, so you don't have room to store two anyway.
Back around the turn of the (20th) century, electric motors were expensive. It was not uncommon to buy one motor that could do multiple things, like this vacuum/grinder/buffer/blower/pulley:
If we start making robot arms at scale, they're going to get cheap.
I'm also not sure people are really going to want bipedal robots walking around their home, blocking the hallways, recording you in your underwear, etc.