In the years following the fungal crisis, alien invasions, rogue A.I. and doomsday cults, Kilgannon came into a steady economic decline. With their investments in Chiba coming to naught with the formation of the Corposuperstate of Atoria, their massive purchase of a highly experimental power source from Kilgannon Silver Energy which - once lost with the rouge technofossil A.I. they had produced to fight the Aminita - bankrupted them in the following legal suit, and the general turning of public opinion against the corporation due to their mishandling of the Chenobek civil war, it was not long before the unthinkable happened. Kilgannon was bought.
Not outright, but the mainland islands were taken from Kilgannon in a hostile takeover by major and mysterious manufactorum company Barret-Dunne, made possible by the massive alliance of other minor corporations - including backing from Kilgannon Silver Energy - which enabled them to topple the corporate titan. The following years were a mess of 'feudal-corpo' politics until Barret-Dunne successfully took total control of the isles.
Now Barrett-Dunne stands a titan of industry, ushering in higher living standards than Kilgannon ever managed (and with higher opinion polls too), keeping tight control of the populace through their shady alliance with the Kilgannon Silver Energy Corporation, and generally becoming ever more isolationist. The outside world is hell, and Barrett-Dunne provides everything you could ever need.
So why ever leave?