We recently played the Civilization Board Game with 3 players and had a similar experience. In our case one of the players was the Soviets (who have the ability to "steal" tech by marching units into other players cities), and also managed to get a wonder allowing them to steal a technology once per turn. This speeded up the tech victory win, however in fairness all 3 of us were within 4-5 turns of a tech victory by the end of the game anyway.
We came to the conclusion that the tech victory was a bit of a cheap win (much like the tech victory condition in the computer game) because researching tech is something you need to do anyway in order to remain competitive at all.
In future games we may simply disallow the tech victory (I don't think that the culture victory will take its place as a unlike tech, getting culture points is something that you need to explicitly work on - often at the detriment of city development / research / military), however my suspicion is that this will lengthen the game considerably. Our game was fairly lengthy (about 3 hours) and so with hindsight it might be that we just weren't being agressive enough with the alternative victory conditions.
Update: Having played a couple more games (included 1v1 games) I've concluded that a tech victory is just a side-effect of being too nice to each other! Charging at each other with traditional armies generally seems to bring games to a close long before anyone is close to a tech victory.