So, I just looked up Vlaakith CLVII on Wikipedia, and it turns out that she's quite a bit lamer than I imagined. I had just assumed she was something cool like "the original Vlaakith who overthrew Gith--she's four hundred thousand years old, and everyone thinks she's really her own great^157th granddaughter, but it's actually the same individual. Every few thousand years Vlaakith 'dies' of old age and is replaced by her daughter, the next Vlaakith, but they're all really the same lich-queen."
In reality she's been ruling for little over a thousand years. Feh. What's the point in being ruled an immortal lich-queen if she's really younger than not just the pyramids but also some elves and human druids?!? In fact, aging is frozen on the astral plane, so she's probably younger than most of the other githyanki. Lame.
Whoever created her had no imagination.