On chieftain the tech race is awfully slow. AI's are so crippled that they need bloody ages to advance in tech, so you cannot benefit on trading / stealing / extorting.
On deity, they can build libraries & universities dirt cheap, and they also trade very aggressively each other. You can hit the industrial age before 1000 A.D.
Try warlord or regent and you'll see a more realistic tech advance. And if you lose, don't give up. It's the difficulty that force you to become a better player. If there's no challenge, there's no nedd to improve. Stick on chieftain and you'll always be a rookie.