It's not worth $3M because of the lot it sits on.
What is your mental model for this then? If the "2BR shack" can be built from scratch for 300k, and the value for the lot + shack is $3M, then the land value is $2.7M. Most expensive real estate is land value, not actual structure value.
What is your mental model for this then? If the "2BR shack" can be built from scratch for 300k, and the value for the lot + shack is $3M, then the land value is $2.7M. Most expensive real estate is land value, not actual structure value.