Writing was invented for economic reasons. The precursor to writing, according to well-respected scholar Denise Schmandt-Besserat’s book "From Counting to Cuneiform" Austin: University of Texas Press, 1992, proto-writing began as a series of tokens that were exchanged as part of an economic transaction. Say you were trading some sheep for some jars of olive oil and wine. The tokens would be exchanged as a symbol of the goods that were to be transferred, as a way of keeping track of who had what. Then, to prevent people tampering, later on the tokens were enclosed in a clay bulla. Then, it was realized that you couldn’t see what was inside the clay envelope, so they pressed the tokens into the outside of the envelope to show what the bulla enclosed. Eventually, people realized that they didn’t need the tokens after all, but instead they could just use the impressions. And thus writing began to be used, as people kept track of their economic transactions.

The next step was the creation of ideograms or logograms to represent words. Initially, these came from the tokens, for goods. Then these token impressions were adapted for the stylus, a wedge-shaped piece of wood or reed that was used to create the cuneiform impressions. These ideograms then came to represent syllables and sounds as well as actual words. This image shows the development of the word “sag” meaning “head” from its original pictogram to its eventual cuneiform image. As this process was happening, the development of the system of writing was changing, and the symbols became less about individual words and more about sounds, moving toward a phonological system.

Astronomy/astrology does not appear to have been a deciding factor in the creation of writing, form this model. But the temple wasn’t just about divining the will of the gods, in ancient Mesopotamia, the temple was an important economic and even governmental institution, with the temple used as a grain storehouse, an economic center. Temples owned a lot of land, and conducted a large amount of economic transactions. If the temple had an influence on the development of writing, it was most likely because the temple was kind of a bureaucratic center which needed to keep records of its plethora of transactions and resources. A good overview of Mesopotamia generally and which includes an overview of this system is Georges Roux’s Ancient Iraq.

I am not familiar with the development of writing in Asia or the Americas, so I cannot speak to the underlying reasons for the development of writing there.

edit: stupid missing parenthesis)