Fap (repeat several times) spooge, or something.
That would imply that the "additive" quality that is making the X-Men and mutantkind stronger and better is taking certain elements from other Marvel franchises (Franklin) and torching these respective sources to nothing. Betsy with the Captain Britain powers (and leaving Brian a Morgan Le Fay drone) was a test run (since Excalibur was an X-Men spinoff to begin with, CB's Marvel UK origin notwithstanding); turning Franklin into a loyal Krakoan and "Limbo-ing" his family would be the acid test of this sort of ADDITIVE status quo.
Maybe that's why Doom steps in in part 2. The X-Men did something to Valeria in #1.