What you say is true - or rather will likely be true in the distant future - but hype aside, robotic aren’t anywhere close to being able to replace unskilled or semi-skilled manual labor with machines anytime soon (except for completely repetitive, mostly stationary tasks like putting a bolt into a single assembly line unit). With such technology decades away, the oligarchs need cheap and obedient wage slaves. Westerners want high pay and rights, and so are too uppity to perform this function, so in the meantime, the more Third World people breed, proliferate, and invade, the happier the oligarchy will be.