Several historical examples exist to show that slave labor can go a long way to providing a nation's foundations. The USA is the perfect example, where slavery was able to kickstart the agricultural industry, and provide a ton of cheap labor to promote advancement. Without the salves, America may be backwards fifty or more years now.
No, xenophobia and nativism will not help a country to advance economically, because xenophobia is not the problem alone. It is not the problem that immigrants come to the country. Rather, the problem is that immigrants come to the country, they are given free food and they are not expected to get jobs.
The fear of other races and a strong sense of self entitlement based on having lived in an area before a so-called immigrant group leads to a break down of trust within a society. This breakdown in trust becomes a self perpetuating cycle, eventually leading to violence and public resources being spent on the security apparatus. These kinds of expenditures may create a boom in the economic sector concerning security and militarism, but in time they lead to a hollowing out of the economy.
Xenophobia and nativism breed prejudice and elitism, both of which are major obstacles for economic advancement. The most successful economies are those that are able to incorporate many different types of cultures and talents into a cohesive workforce that is determined to advance. This type of mindset requires openmindedness and a willingness to be unconventional.
I think when a country shuts out foreigners and foreign ideas then they limit themselves for innovative thinking and creativity, I think overall this hurts business innovation and economic progress, so I think xenophobia actually actively harms a nations economy instead of improves it, I think free trade of goods and ideas is vital.