.... “Typically people tear down a house because of social or economic reasons; it’s rarely because the lifespan of the material of the house is done,....

Nothing to do with life span but obsolete building standards ( e.g. insufficient insulation ... ). Or poor foundations, dangerous wiring, .... There is also a point where it is cheaper and more practical to build new rather than renovate. Lastly today houses are far larger and better built than say 50 or so years ago - small houses under say 1000 square feet are a marginal proposidion ....

Modular construction is not a cure all.