Why? You can rush-finish the parts (with overflow and chops) and techs (with GPeople and GAge) faster than AI, and having a trading partner throughout the game is much better than learning all by yourself - for fastest finish you would feed with prerequisistes a friendly "tech hamster" to trade with him later. However, it can't be altered for finish techs.
You haven't mention that you were speaking about SS victory (I myslef aimed a time vic). In that situation I agree with you, with the addition that SS victory became much harder since AI can reach a cultural victory about 1750-1800 AD (I don't know when in deity). I won't try an SS/deity game.
Flóri