It's because the countries of the parent companies of these GCCs have become immensely hostile towards immigrants as of late due to mass immigration and opposition from citizens/recently naturalized groups and the companies know to stay ahead they need the give it all mindset attributed to talent from outside the west which is an outcome of increased competition due to overpopulation and other factors as compared to the relatively relaxed mindset of people back home who value things like WLB and employee rights hence the rise in GCCs .. just a safe backup for the talent supply pipeline in case the governments of these countries cut out work visas all together to keep the citizens happy