I think the X-men narrative didn`t really take Genosha as a symbol or even a plot point until Hickman`s who`s taking a more realist approach to an event like that happening in the MU, it should have had an impact since Morrison`s run but imo my guess is that he just wanted to get rid of the island and build a mutant society closer to the X-men mansion in NY this fact really made me not care about his run that much given he himself didn`t take seriously the events happening in his own story and Planet X was the worse for me, even decimation was it`s own thing and Genosha was forgotten for a long time until now, except of course for the characters more affected by it Magneto, Emma and Lorna.