I don't think the entire world is that callous, but a lot of people are, especially professionally... Some of my guys go on to great success and never look back, some send a thank you, some never leave, and others have life issues and end up in bad situations that I can't control.
About moving - I'm lucky enough to have lived and worked in a lot of places around the world over the years, and the way I treat people, the way I'd like to be treated, and the way I am treated tend to be 3 different things... But its nice when things go well and I'm not complaining, just observing... I've let chefs sleep on my sofa for months - when they open their own restaurant years later i go, and pay for my bill myself because I don't begrudge anyone success from the things I've taught them.