US population 300M. H1B is capped at 65,000 a year with some exceptions for universities. Restricted to 'professionals' with university degree. Employers need to show H1B are paid the same and should not affect labour market/ salaries.
For Singapore's population, the percentage of H1B 'equivalent' per year is probably higher. Anybody know what is it?
But it is completely true US/ Canada/ Australia have benefited greatly from relatively small numbers of immigrant workers. Like our forefathers, immigrants are hard-working, have lower expectations, less demanding. Also more vulnerable. Little political power. Easier to get more from them for less.