Almost all projects of this kind fall apart within a decade because too many people drop out of the study, or funding for the research dries up, or the researchers get distracted, or they die, and nobody moves the ball further down the field.
Case todos os proxectos deste tipo véñense abaixo nunha década porque moitas persoas abandonan o estudo ou os fondos da investigación rematan ou os investigadores perden o interese ou morren, e ninguén continúa a investigación.