Pre 1964 the luxury of choosing where you lived was largely reserved for the rich, who had time and money to organise their integration. There were fewer concerns over security, abuse of social security benefits and so on which has created some of the administrative requirements.
For the poor it was another story. People went where work was, and that was the springboard but with many constraints. Or they were refugees and moving countries was not easy! My grandparents can attest to that!
You are referring to people moving here while the UK was in the EU and had the fundamental right to live and work here. Ok some didn’t follow the rules but we had to do a ton of paperwork when we arrived. And absolutely no english speaking help available, or internet forums.