Why don't we have more information about the Indus Valley civilization?

Responses

Most archaeologists and historians prefer to work on the Mesopotamian and Egyptian civilizations.
Most archaeologists and historians prefer to work on the Mesopotamian and Egyptian civilizations.

Only one ancient city in the Indus Valley has been discovered and explored.
Only one ancient city in the Indus Valley has been discovered and explored.

The ancient people of the Indus Valley purposely obscured evidence of their existence.
The ancient people of the Indus Valley purposely obscured evidence of their existence.

Archaeologists and historians have been unable to decipher the Indus Valley writing.

Archaeologists and historians have been unable to decipher the Indus Valley writing.

I suspect also:

Only one ancient city in the Indus Valley has been discovered and explored.

Yes, that is another reason why we have limited information about the Indus Valley civilization. Only one ancient city, Mohenjo-daro, has been extensively excavated and studied, while many other sites in the Indus Valley remain undiscovered or unexplored. This lack of comprehensive archaeological exploration hinders our understanding of the civilization.