The major source for our current Egyptian chronologies are the works of an Egyptian priest called Manetho. They are still the most popular used today, mainly because they are viewed as the most complete and, thus, the best we have. This is despite the fact that both secular and Christian Egyptologists know that these ‘standard’ chronologies are in desperate need of revision.
There is good reason to think these greatly exaggerate the duration of the Egyptian civilization.
Many other historical events are dated with reference to Egyptian chronology.
[edit] Consequently it is likely that the Egyptian civilization was established not long after the flood, probably after the Tower of babel confusion.
This is one of those times where creationism has apparently failed to notice the previous century or so of historical and scientific research.
I have next to me a chronology of ancient Egyptian history written in 1904. It dates the start of the first dynasty to 4,400 BC. As you can see, you are quite correct that a naive counting back through Manetho's king lists causes one to overestimate the antiquity of Egyptian civilisation. However, you are quite wrong that this is what modern chronologies are based on. Thankfully, people didn't stop doing research in 1904, and with the advent of radiometric dating modern estimates put this about 3,100 BC.