Why do archaeologists know so little about the government or religion of the Indus Valley civilization?

Archaeologists know little about the government or religion of the Indus Valley civilization primarily due to the lack of decipherable written records, as the Indus script remains undeciphered. Additionally, the ruins of their cities, such as Harappa and Mohenjo-Daro, provide limited insight into their political structures and religious practices, with few large temples or palaces to indicate centralized authority or organized religion. The absence of monumental architecture and the uniformity of urban planning further complicate efforts to understand their societal organization. Moreover, much of the archaeological evidence is open to interpretation, leading to various theories but little consensus.