Thing is, we are all different, some children deal well with adverse situations and build mental strength others don't. I know nothing about Kygrios' childhood so it would be wrong to speculate but he's clearly got some mental health issues. Early success and making a lot of money doesn't insulate anyone from struggling with their mental health and perhaps it makes them more vulnerable when faced with adversity. In 2016 he was ranked no 13 and in 21 he was 93, not the usual trajectory for someone with his talent and he didn't play at all for a while. His behaviour is very unpleasant at times but I think it hurts him more than anyone else. He's not the first player to behave badly and I suspect he won't be the last as it's a physically and emotionally intense game.