... the intended market is explicitly people who are already homeowners, in CA or WA, and have space for an ADU in the backyard, which they could use as supplem

... the intended market is explicitly people who are already homeowners, in CA or WA, and have space for an ADU in the backyard, which they could use as supplemental income for renting. Are there really many people with the finances to buy a $400k ADU for their backyard who want to rent it? That seems unlikely. More likely these are targeted for home studios/gyms or in-law (or adult child) suites. I have nothing against ADUs, and wish more areas allowed them, but $400k is an absurd price.