Because, not only do migrants need to fit the criteria of jobs needed, one aspect is having a job waiting for them.
How many have left those jobs?
European workers are fleeing the UK economy during the pandemic
The loss of EU workers could make Britain's economy less dynamic.
www.google.com
NHS winter crisis fears grow after thousands of EU staff quit
Mass resignations after Brexit vote compound health staffing shortages
www.theguardian.com