Sorry for this discussion quite late. As a one-time student of anthropology and avid "armchair indologist", I think it is important to recognize what culture is. It is a set of rituals, beliefs, and norms established by a society to survive and flourish in its environment. As the environment changes, either through emigration or technology, the culture changes accordingly. However, the basic elements of the structure - general views on divinity, food, relatives, and people generally remain fixed.
There is one thing, however, that dramatically changes culture and that is outside invasion by a dominant society, which can leave an indelible impact on a society that can last many generations. In our case in South India, particularly Tamil Nadu, such an impact came less from the Muslims as it did from the British, resulting in our love for the "white man's world". Such an inherent love for the dominant culture, even when the dominant culture is not present is a form of psychological/cultural conditioning called "learned suppression". The only to heal from it is when a healthy representation of the population - anthropologists feel about 1/10th - begins to rebel against this conditioning and establish the old criteria for cultural growth. Such a healthy representation has not yet happened among the Indian community.