Do we have any reason to believe there's giant blocks of pure, rare metals on the moon or asteroids?
So far there's no evidence to the contrary. Speculative interest says "keep digging, there's bound to be one out there" among the rocky asteroids. Heck, even "comet water might" bring a price, given trends.
There's no brown people on the moon you can give a dictator weapons to in exchange for keeping the people selling their labor and resources for peanuts.
If you think the next wave of neocolonialism wouldn't consider indentured servitude and/or conscription, well... I guess we shall see. You don't need indigenous people, just poors.