Another huge blocker (that is essentially just cost too) is maintenance. These things are like 1000x more complex than a car, need to work in a diverse range of environments, handle water, household chemicals, different humidities, kids, etc… maybe eventually robots will service robots but that seems very hard!

And talking of kids, these will have to be exceedingly safe, a 6ft machine falling on a child is probably a worry most households could do without.