"I during the 1950s we had very high levels of immigration and the followingdecade of the 1960s we had an economic boom with a decade's GDP growth of 5%+P/A."
Those migrants came to add to the country and its safety net unlike the ones that come in today.
Look at the refugees from Ukraine, they're fleeing to the nearest safe port to them unlike the garbage that flies across the world to 'feel' safe.