I agree with you but I think it's yet to be shown they're less happy than modern people. Happiness seems to be relative, and bringing them in from masters of their environment (if they are) to lower status advanced humans could easily drop their happiness even if it improves things in an objective manner.
I've absolutely no love for the concept of "nobel savages" or "primitives living in harmony with nature" but it's possible they're just as happy, even given disease, murder, etc.
I may have read too much Nietzche and Schopenhauer but I belive using a fleeting emotion such as happiness as the sole basis for measuring the quality of one's life is a terrible idea, yet sadly it remains an incredibly popular concept in pop-science self-help books.
I've absolutely no love for the concept of "nobel savages" or "primitives living in harmony with nature" but it's possible they're just as happy, even given disease, murder, etc.