MustangV8 you really think the spending power of 100USD here in the UAE is the deciding factor on whether or not someone comes from their home country. You are way off the mark if you do. None of us can ever get citizenship here and bottom line is we are all here to save a nest egg for our future (you're crazy if you're not). So... a Sri Lankan who can save 100 USD a month (about double the average monthly salary in Sri Lanka) will be much more likely to come here and more importantly stay than an Australian who can save 100USD (less than one tenth the average monthly salary in Australia). It's basic economics, right or wrong, workers from the subcontinent and some asian countries will come and stay for a lot less money, than people from countries with a higher average salary.
So to answer your last statement, "I must be missing something", yes you are. The cost of living is the same for all of us while in the UAE but the majority of us are sending home all our savings to our home country either regularly now, or in one lump when we leave (and as I said we all have to leave at some point), so the relative value of the money saved in our home country is the most important factor of all.