The popular perception that land is a good investment comes from the wealth of the 1950s allowing tons more people to have fond memories of vacationing somewhere picturesque and then the interstate highway comes along making those areas logistically practical. Even if you have a pile of hazmat sitting on it land that's within a ~20min drive of the ocean is not going down in value.

Add to that the tax incentive structure and buying a house that's sitting on a huge chunk of land that can be subdivided years down the road if desired makes good sense for many people.