Can culture be boiled down to material motive?

Marvin Harris seemed to think so. he thought so to the point of publishing that the "Indian Sacred Cow" is sacred because of the lack of combustibles on that subcontinent, and cow dung filled that niche. Granted that is an extreme example of what is called Cultural Materialism (definition below). However I see so often people explaining away cultural institutions through psychology and economics, and I'm prone to do it myself. I assume that most of it can, or can at least come up with Guns Germs and Steele type scenarios which could explain them. What say you?

http://en.wikipedia.org/wiki/Cultural_materialism_(anthropology)
Cultural materialism is an anthropological research orientation. "It is based on the simple premise that human social life is a response to the practical problems of earthly existence" (Marvin Harris).[1]
It was influenced by the writings of Karl Marx and Friedrich Engels, yet is a materialism distinct from Marxist dialectical materialism, as well as from philosophical materialism. Thomas Malthus' work encouraged Harris to consider reproduction of equal importance to production. The research strategy was also influenced by the work of earlier anthropologists ... who, in the 19th century, first proposed that cultures evolved from the less complex to the more complex over time.

Cultural materialism is a scientific research strategy and as such utilizes the scientific method. Other important principles include operational definitions, Karl Popper's falsifiability, Thomas Kuhn's paradigms, and the positivism first proposed by Auguste Comte and popularized by the Vienna Circle. The primary question that arises in applying the techniques of science to understand the differences and similarities between cultures is how the research strategy "treats the relationship between what people say and think as subjects and what they say and think and do as objects of scientific inquiry" (Harris 1979:29). In response to this cultural materialism makes a distinction between behavioral events and ideas, values, and other mental events. It also makes the distinction between emic and etic operations. Emic operations, within cultural materialism, are ones in which the descriptions and analyses are acceptable by the native as real, meaningful, and appropriate. Etic operations are ones in which the categories and concepts used are those of the observer and are able to generate scientific theories. The research strategy prioritizes etic behavior phenomena.

Theoretical principles

Etic and behavioral Infrastructure, comprising a society's relations to the environment, which includes their etic and behavioral modes of production and reproduction (material relations).
Etic and behavioral Structure, the etic and behavioral domestic and political economies of a society (social relations).
Etic and behavioral Superstructure, the etic and behavioral symbolic and ideational aspects of a society, e.g. the arts, rituals, sports and games, and science (symbolic and ideational relations).
Emic and mental Superstructure, including "conscious and unconscious cognitive goals, categories, rules, plans, values, philosophies, and beliefs" (Harris 1979:54) (meaningful or ideological relations).
Within this division of culture, cultural materialism argues for what is referred to as the principle of probabilistic infrastructural determinism. The essence of its materialist approach is that the infrastructure is in almost all circumstances the most significant force behind the evolution of a culture. Structure and superstructure are not considered "insignificant, epiphenomenal reflexes of infrastructural forces" (Harris 1979:72). The structure and symbolic/ideational aspects act as regulating mechanisms within the system as a whole.
The research strategy predicts that it is more likely that in the long term infrastructure probabilistically determines structure, which probabilistically determines the superstructures, than otherwise. Thus, much as in earlier Marxist thought, material changes (such as in technology or environment) are seen as largely determining patterns of social organization and ideology in turn.