This thread brings up a good point. I often felt that way myself.
Everyone gets to steam engines or tanks many centuries too soon at Regent or even Monarch. A too fast tech tree development is probably why Firaxis threw in all that crazy corruption as a late fix, or an attempt at a fix.
Again, here we are having to MOD the game OURSELVES because something isn't right. It should have been done in playtesting before marketing, asuming there was playtesting.
If you recall the scenarios with Civ 2 we were able to conduct entire (shortened) games in a single era with a more limited progression of new advances, be it the WW II, WW I, Alexander, Muslim Expansion ("Cross and Crescent" as I recall), and others.
In WW I we could develop Poison Gas, for instance, but Stealth Bombers were no option; the time frame would have limited that anyway.
So here we have another reason why scenarios we so useful.