What is rich actually? I still don't understand how can an entire nation be rich without someone (immigrant) or machines doing your job.. or access to latest ga

What is rich actually? I still don't understand how can an entire nation be rich without someone (immigrant) or machines doing your job.. or access to latest gadgets? but i still see people struggling to pay for education, finding jobs is extremely difficult etc.. people are still low/middle/upper irrespective of the country. there are several developing nations where people don't have so much struggle to live.