I am glad you mentioned automobiles! They are among the most heavily engineered everyday product that we use every day, and this engineering and cost optimization has been going on for close to a hundred years now. So, I would read this same statement as "$20k and 100 years of engineering gets us a lot" rather than "$20k gets us a lot". I am hoping better engineering and the wonders of modern supply chains will get us a home robot at 1/10th of the current price when the time is right.
I understand why it is so expensive, since it is not a mass product. Or in other words, it should be 10x cheaper, if it would be a mass product.