Yes, the days of holding on to every last hair is pretty much gone, unless you're the president. Shaved heads are so common now, it's just another haircut.
As far as young people go, maybe some want to try the baldie look, so they use the excuse that they are starting to thin to take the plunge. You're right Semi, there are different haircuts can hide slight thinning.
Like I tell people, if a guy has a totally shaved head, in almost all cases, it's because he wants it that way.