All that aside, does anyone have a generic range for these components, for example say $x/ linear foot for a 20-ft wide, standard roadway with extruded curb & gutter, say doubling that if your grades are more than Y degrees, or tripling if more than Z degrees?

There has to be a missing component.

I've heard of thermostats that only allow temperatures within a certain range or that have useful Wi-Fi components for managing utility usage.

@Tsai Richard, there are many components in a house and they are depreciated at different rates.  

There are manufactured ADUS offered, panelized (where they are built off site and components hauled to the site for installation, and of course stick built.

You’ll need to contact the Environmental Section of the Department of Neighborhood Services.

Apparently, even though I had the electric checked and some components of it updated (based upon the inspection) this house needed a total rewire. 

Major home components that die. 

I personally only consider properties with some type of subsidized housing component currently because the possibility of a second lockdown makes me nervous about properties with market rate tenants.There are instances where the subsidy programs will cover 100% of the tenant's rate, but that'll vary based upon the program and the tenant's individual situation because most programs typically assess a tenant's financials and living situation before determining how much of the rent they'll subsidize. 

The second could be a property to fix up, but as soon as you involve retail components you are into commercial building code.