Wonderful answer I thoroughly enjoyed reading that. You must have some sort of background in this stuff?

So going beyond the magnetic shielding concept, what about the idea that an active core and volcanoes are required to release the gases into the atmosphere in the first place?

Edit: scratch that I just seen your other comment answering that question already.

Losing the requirement for having an active core, I would assume, would drastically increase the number possible habitable worlds out there.

This is fascinating stuff to think about, even though it is basically completely irrelevant to day-to-day life.