This is always an interesting theory. That the Egyptians, or the Mayans, or the Minoans.... or whoever we want to name.... that some how they had long lost knowledge that we don't have now. Of course.... they didn't have electricity... but they were super smart. Much more than us. And the best part about this, is we don't even have to name what that long lost knowledge was... because its lost.
Is it "smart" to depend on electricity as much as we do? What's so "smart" about a grid upon which large portions of the population depend for their very lives and entertainment? Folks may equate technology and electricity with "smarts," but I'm not so sure. Besides, you don't need electricity to brew beer.
You've seen the stone structures they left behind.
We can't figure out how they built such gigantic buildings, even with the physical evidence they left behind.
Egyptian glyphs depict all kind of light bulbs and flying machines. Mayans left several solid gold miniature aircraft.
They weren't cave dwellers. They obviously knew some things that we do not.