On the one hand, trransformative techs are very historical, as we've seen in the last two centuries. Including the benefits for the civ citizens would reflect the wide scope of changes in the last few era(s). On the other hand, Civ the franchise has also featured snowball mechanics that risk making one (or a few) factions overpowered in just a few turns. In Civ3, after researching Military Tradition which unlocked a powerful unit, strong players (and AI) can invade and overwhelm their neighbors. Getting railroads in both Civ3 and Civ4 (and probably Civ2, but it's been a long time) dramatically changed the number of turns required to move troops around. Yes, in the later eras, each turn represents a year. So the transformative effects that
@Catalytic described might take place within 20 or 50 turns. But their potential for snowballing is massive, from a gameplay perspective.
I would go further; while some leading real world civs developed electrification, the effects were quickly spread to countries/civs that did not. They hired companies from the other countries/civs to install it for them. How do we model that, in-game? A Civ3-like trade agreement, trading Gems for Electricity?