Unfortunately some of Egypt's abilities and knowledge have been vastly exaggerated. They had strong rivals to the north for much of the periods where the empire was the strongest. In later periods Pharaohs ruled for shorter periods of times. In many of the ruling eras there was massive civil and political unrest. Keeping the country together and under control seems to have been more of a priority. This is especially true during periods where the Nile didn't flood properly and you had famine and drought. I strongly recommend if you are interested in the intricacies you read The Rise and Fall of Ancient Egypt I don't think there is one nail in the coffin answer to your question. The Eqyptians after the unification definitely had designs on conquering lands further to the north. However each time they were met by strong adversaries and a myriad of circumstances that prevented this from occuring.

First, Egypt was expansionist, with the Egyptian Empire stretching from what today is Sudan all the way up to Turkey by the 15th century BC. If this were a state today, it would dominate the western Mediterranean and the Middle East.

With that being said, I think it's a little strange that you're assuming there is a correlation between having relatively sophisticated technology and expansionism. I don't think it's accurate to say that a state with a relatively high technological level should naturally be an aggressive colonizer. To give an obvious example, Germany was quite advanced technologically compared to other European countries in the 15th century, but was a collection of small kingdoms. We could also point to China. Some Chinese dynasties were certainly expansionist, but in the late classical to early modern periods, for instance, they were not nearly as expansionist as and frequently fell victim to the Xiaonu, Jurchens, Mongols, Manchus, etc., who generally had much less access to material technologies than the Chinese.

For what it's worth, while groups like the Phoenicians founded a number of colonies, the Greeks really got around the Mediterranean in terms of colonial expansion. This may in no small part be because Greece had a rather serious problem feeding it's growing population. There's certainly a number of laws on the books forbidding grain exportation and it's not a stretch to think that As the Greek population grew beyond what the relatively rough-scrabble landscape could sustain, pressure would favor looking outward.

The Egyptians didn't the same set of problems that would be conducive to founding colonies.

I'm going to refer here to Harold Innis's interesting thesis into the relationships between power and stability and the evolution of civilizations, and communications and the monopoly of knowledge.

Innis simply argues that the development of communication means i.e writing, scripts, tools and media, reflected greatly how a stable or expansionist a civilization could become. Or, to paraphrase him, the monopoly of a mode of communication will eventually lead to the rise of another mode, by the same or a different group of people, to replace the old system, and spread knowledge in a particular direction. This transfer of knowledge would give rise to social and political changes.

For example, the Greek relied mainly on stone as a medium, which dealt with the challenge of time, since it's durable, but failed to deal with the issue of space - how can we move it from one part to another when its heavy. Owing to this impracticality, stone was not conducive to running a bureaucracy of a vast empire.

In the same theory, the Roman's use of papyrus (which they got from the Egyptians) enabled them to regulate, organize and efficiently rule an empire with a central administration.

Egypt relied on the stone for most of its life as a medium, and as such it was not appropriate to rule an empire. When the Egyptians began to use papyrus, its use led to the creation of another script, the hieratic, but it remained more or less monopolized by the priests. Their power grew as a result since they limited the spread of knowledge to other parts of Egypt. The adverse effect was that it confined science to the time-related areas e.g. when the Nile tide will happen, the after-life, death and immortality. In other words, this monopoly, "supported an emphasis on religion and the time concept, which defeated efforts to solve the problem of space."

Summary: en.wikipedia.org/wiki/Empire_and_Communications

The book: Empire and Communications, 1950, Harold Innis