Re: The Emergence Of Superhumans
The introduction of superhumans is a special case of Alternate History. The general rules of AH are:
1. The farther back the change, the greater the effects on "today".
2. The larger the change, the greater the effects on "today".
3. The more visible the change, the greater the effects on "today".
Exceptions abound, of course.
The introduction of superhumans is typically a large, visible change. (It doesn't have to be, but it usually is.) It actually takes a concerted effort to explain why the introduction of superhumans doesn't make more of a change than the normal comics trope. And the longer ago the introduction of superhumans, the more effort it takes.
As with any AH, you can reason forward, or reason backward. To reason backward, decide what changes you want in place and figure out how the introduction of superhumans got you there. To reason forward, introduce superhumans at your chosen point and extrapolate. In either case, you should either insure that you are the SME for the historical period(s) in question for your local gaming group, or that the the SME(s) is (are) willing to help you and/or grant you the benefit of suspension of disbelief when you (in their eyes) violate plausibility.