Robots building houses wouldn't solve the problem. The cost of construction makes up a small part of the price of a house or apartment in attractive cities like SF, NYC, London etc.

Separately, I'm not sure I understand your point about price vs. value. In SF or London, apartments have high value (evidenced by people willing to pay high rent to live in them). Maybe in some places (Beijing?) apartment prices are hard to justify based on rental yield. But what makes you think home prices in general are divorced from home 'values'? What would make prices go down that would not also not decrease whatever measure of 'value' you're using?