Another point to consider:
For me anyway, I realise that (based on family history), over time I will lose MOST of my hair, and I also realise that no amount of surgery/treatment will ever allow me to maintain a full head of hair for an indefinite period. The main reason I want a hair transplant is for confidence, confidence when dating, confidence when I start looking to perhaps get married (could be soon). I don't think however that once I am married that I will be AS concerned about my hair loss as I am now. Does this not come into account when deciding whether or not to give young men (perhaps even those as young as 20) a hair transplant?
In a nutshell, myself, and I'm sure others, want to look as good as they can whilst they are young, and do not care so much about future hair loss.