So What's Wrong?
Nothing’s wrong. Gross’s explanation for the kitchen fires in India rings true, but it doesn’t explain why other societies that have escalating dowry don’t have kitchen fires. Nor does it tell us why dowry persists in India despite being outlawed since 1961, or why dowry—which, after all, only occurs in 7.5% of the world’s societies—exists in the first place. But Gross’s theory is a first-class example of theory at the local level—where research begins.
Goldstein’s theory is attractive for understanding the Tibetan case of fraternal polyandry, but it doesn't say anything about other cases of polyandry, like the one studied by Hiatt in Sri Lanka (1980). Over the years, other case studies of polyandry, in Tibet and elswhere, have either supported or not supported Goldstein’s theory (Levine 1988; Levine and Silk 1997). As the idiographic studies build, we’ll gain better and better understanding of the nomothetic principles, if any, at work. In the meantime, E. A. Smith (1998) and others have applied an an evolutionary perspective to understanding polyandry and other scholars have tested the effects of structural changes on polyandry.
Paredes’s theory helps us understand how the Poarch Creeks maintained their cultural identity, but it doesn’t tell us how other Native American groups managed to do this or why some groups did not manage it. Nor does it tell us anything about why other ethnic groups maintain or fail to maintain their identity in the United States or why ethnicity persists at all in the face of pressure from states on ethnic groups to assimilate. Others can try to make the theory more nomothetic.
In any science, much of the best work is at the idiographic level of theory making.