Amazing how /. technical elite become downright ultra-conservative assholes when traditional subject are concerned. Your post and many others would be the equivalent telling a woman in the 80's that there is no reason she would need a micro-wave if she cannot take the time to cook properly for her family.
There are plenty of cases where a parent is legitimately separated from his kid:
1. divorce: my wife is from a different country - if we divorce and she goes back closer to her family, it would take me at the very least several months to sort things out. My case is easy tough, I can consider moving at all. There are cases where it is simply not easy legally (Australia - UK is already a problem and that's an easy one culturaly, what about China / Russia / Japan) What stuff preventing the guy to move like uninteresting resume, lack of skills.
2. he is deployed, a sailor, or anybody that needs to be months away from home. Maybe he wasn't 4 years ago. Crisis man.
3. crisis. I have friends (with older child) that have had to take work several hundred miles away from home. People hit by the crisis are not the kind that can afford a personal jet for commuting. Moving a family to a new city to follow an unreliable jobs can be expensive and almost as bad for the kids. Not even considering that the kid could have health issue or other specific needs making it even harder to move.
4. shit happens. I known/heard of people being separated for tons of shitty issues like health reasons, legal problems, visa problem.
The reason there used to be no reason for a 4 year old to have a mobile in those situation was because it was socially acceptable to not interact with your kid in those conditions. I have never seen anybody suggesting that we should make a law prohibiting soldier, sailor to have a family for example. There is a possibility this guy is just trying to do better than what society is expecting him to. That is also his fucking right not to expose all the details of his potentially shitty situation.