Egypt was incredibly well protected. To the east was the near endless desert and to the north was the untamed Mediterranean. Their only threats were from the east and the south. The eastern passage was bottle necked by the Red Sea. The Kushites to the south were trading partners and later were conquered by the Egyptians (who were technologically more advanced).
Mesopotamian civilizations were separated by the Zagros Mountains which meant that there were almost always multiple factions competing for superiority.
However, the Indus Valley cultures at Harappa and Mohenjo'daro were by far more advanced than their western counterparts. By 2600 BC, they civilizations almost encompassed the entire Indus basin dotted by over 1,000 cities. Every house had access to water (wells) and drainage (covered drains that flanked their streets and roads). They had granaries and warehouses for storage as well as advanced dockyards with early pound locks. They even had huge brick walls (although this was most probably used for protection against flooding rather than for military use).
They were able to produce works in clay, bronze and gold since they had systems to measure weight and distance with great accuracy. They also had major trade routes over land and by sea from which they got most of their wealth.
