I don't think you can put anything "that people shall be happy" in this aspiration prayer, the opposite would be more appropriate: "That they be depressed to the bone, that they decrease in number, that they decrease in industrial productivity! etc..." an other kind of wishing prayer would be self-deception,
Why on earth not? Happiness is not a deluded fantasy where one ignores the harm one does to the planet. We wish for beings happiness *and the causes of happiness*. Cause of happiness <> climate change disaster (perhaps. I'm not omniscient, so i can't say for certain that is true or not true. )
My point is, the four boundless are boundless. Wishing for beings happiness is more than 'people', more than earth, more than milky way. Its boundless to infinity and beyond! To condition it to this small place, circumstance, and time is not the point of the aspiration.
Ever see a fractal's graphical representation? Its the same sort of pattern from the infinitely small to the large. Using this as an example, i see it as an analogy of samsara, from small to large, the same patterns that create suffering. So may i match the aspirations i make to that pattern, boundless to the small, also to the large.
So if its boundless, then one can wish for beings happiness and not know limit of space, time, condition and presumption. One can wish for all beings happiness and know its not just a small group of humans on a little planet in a backwater galaxy.