I guess I'm not very clever because I don't understand how encouraging inward immigration in search of cheap labour isn't akin to a ponzi scheme. Another thing

I guess I'm not very clever because I don't understand how encouraging inward immigration in search of cheap labour isn't akin to a ponzi scheme. Another thing I never see discussed is: what is the top limit to the population a country can carry without things becoming miserable? Surely at some point inward migration will have to stop unless we aim to have every single citizen of the world living in a single country, and what then? Also, how is it morally or economically justifiable to let existing citizens languish on unemployment benefit whilst solving the problem of their lack of participation in the labour market by opening doors to cheap migrants? It seems to me like if we care about our fellow citizens we should all get used to paying higher prices in support of them, which might enable them to obtain the necessities of life in a more fulfilling manner.