Predictions: Future simple v. continuous

Hi,

I am teaching a short language input class tomorrow night as part of my CELTA training. The topic of the lesson is the use of the future simple and future continuous with reference to predicting the future. The context is predictions about "the future" made in the 50s and 60s that never came to be.

I'm having a hard time differentiating between the two. The best I can come up with is that the future simple is used when there's an expectation of something happening, but no way to affect it, whereas the future continuous is used when there is some way to be sure.

But honestly, I can't think of an example, particularly in reference to the source material, in which the two can't be used interchangably.

Help!

As a general prediction, I am not sure that I can see much difference between these:
In the future, people will wear bacofoil suits.
In the future, people will be wearing bacofoil suits.

However, if we put a time reference in, things changes:
By 2020, people will live on the moon.
By 2020, people will be living on the moon.
In this case, the second sounds much more natural to me.