Immigration laws in a lot of countries are incredibly strict. To move to many countries, you will need to prove that you are able to support yourself, and that you have skills that the country needs – or that you have enough money to contribute to the economy. In some countries, you can get residence permits if you invest in the country and create jobs, or if you have a highly in demand skill (for example if you are a doctor, or a craftsman in a trade that has a current skills shortage).
The reason that immigration laws are so strict, is because countries with a high standard of living want to protect that standard of living. They don’t want to end up in a position where huge numbers of people are coming to live in the country, but then finding that they cannot get gainful employment, so they need support in the form of housing assistance, medical care and benefits.
That’s not to say that all immigrants are there to simply claim benefits, far from it, but there has to be something to stop people leaving one country with perhaps a less favorable benefit system, to put drain on another country that would support them better. Medical tourism, education tourism, benefit seeking, are all realities and put a challenge on the countries that are the world leaders in those areas.
Immigration laws attempt to control that, allowing people with family ties to move over, but discouraging people who would not be able to make a good life for themselves from traveling. Perhaps one day we will have open borders for all, but the global economy can’t support that yet, so the reality is that strict immigration controls will be here for a long time to come.