I wonder if Civilization doesn't include a technology capping option because the developers never thought to include it, or because they decided against it. 
What I mean by tech capping is essentially a complement to starting time period. At the beginning of a game, during setup, it would be awesome to have an option that would stop technology during the classical age, if, for instance, I wanted to play the entire game with only classical technologies.
As it stands now, civilizations like Rome sometimes don't have much time to use their special units. A full game using Legions and Ballistae would be great.
Are there mods for this?

What I mean by tech capping is essentially a complement to starting time period. At the beginning of a game, during setup, it would be awesome to have an option that would stop technology during the classical age, if, for instance, I wanted to play the entire game with only classical technologies.
As it stands now, civilizations like Rome sometimes don't have much time to use their special units. A full game using Legions and Ballistae would be great.
Are there mods for this?