Well, there is immigration and there is immigration and not all forms of it are equal. In some developed countries a gradual intake of people, generally highly skilled, adds to their work force in a constructive way but mass immigration is also a weapon of war. You saw it when the "goody goody gumdrops" team invaded Syria, "How many millions can you economy support" and of late, folks in eastern Europe are being asked the same question. Its easy to be a purist when you don't have a flood of people on your doorstep.
I was more inclined to agree with Alan Jones with his comment on modern kids, my gen walked to school and later on a small pushbike my mum bought for me. No electronic gadgets in the 1950s so you spend much more time outside. Air conditioning in schools ? Sport was normal, the reason why kids were generally fitter, faster and skinnier.
Then they were generally healthier as well, playing outside in the dirt, skinned knees, mud, climbing trees or cliffs, all those dangerous things that kids did back then gave them immune systems like cockroaches and YES, we got pronged with a whole host of vaccines in the early to middle 50s with well proven vaccines where the kids were not guinea pigs for drug companies.
Treat kids in modern western societies like they need to be protected from life and you end up with the fat, sloppy, lazy thing you have now.
