Remember that the machines require electricity, so you have to also include the land needed by the power generation and transmission equipment. And assume that

Remember that the machines require electricity, so you have to also include the land needed by the power generation and transmission equipment. And assume that the power comes only from CO2-neutral sources (very dubious assumption). And then we remember that vacuums make a lot of noise and people don't like living near noise, whereas living next to a forest is fine, so you need land padding too.