Elizabeth Warren addresses this trend in a paper showing most homes' square footage went up to add a second bathroom in comparison to the middle of the century.

Elizabeth Warren addresses this trend in a paper showing most homes' square footage went up to add a second bathroom in comparison to the middle of the century. The cost of labor to add a bathroom and the raw cost of the materials in relation to that low cost house is probably also not worth it either because if we're talking $40k houses I would heavily bet that the property is in an area with no non-minimum wage jobs within reasonable commute distance nor retirees that need income.