Without bringing job density into the equation, the demand is much much higher from the land value increase when zones move up. Is not at all unheard of for a SFH that was worth max 500K on the SFH market to be bought for over a million by developers when an area has gotten upzoned. Now, going back to jobs, in practicality, allowing upzones, also tends to bring way more jobs - more coffee shops / corporate towers etc.