Is the tech tree too slow in this game?

[gauch0]

I'm playing my first long campaign, and for the first time I've researched the tech that will allow me to produce geishas. Unfortunately, I'm one province away from victory, and it will take me six turns to build the city improvement that makes geishas. I'm finding myself stalling just so that I can see a geisha unit.

What does everyone think about the speed of progression through the tech tree in this game? So far I have never seen a geisha, and I have never built a legendary building. I rarely get through half the techs before I win. Should the tech progression be faster? Or am I playing wrong?

(FYI: I am playing on H/H.)