"That is, how much value a parcel creates for the community compared to how much value it consumes simply by existing as land. Think of it like this:

Net Contribution=(Economic Output in $)−(Land Value in $)"

This calculation is shady. Land value fluctuates and already "bakes in" the predicted economic output... but multiplied across decades. Not to mention, land doesn't consume value by existing. the value never goes anywhere. Its opportunity cost, not a decrease in actual value.

Yes, there is value "missed out on", but it hasn't been destroyed. Because it never existed. And that value wouldn't have appeared out of nowhere. it would've required using up other resources that the parking lot wasn't.