The cumulative achievements are not counting up on Steam. For example, my “Through the Ages” achievement is showing as “0/0”…I have completed every campaign mission and done several Skirmishes (Enough to almost finish two civ masteries). I could be wrong, but I’m almost certain I’ve aged up at least a time or two.
EDIT: For clarification ALL of the cumulative achievements are showing as “0/0”, not just this one.