Real love is the love that sometimes arises after sensual pleasure: if it does, it is immortal; the other kind inevitably goes stale, for it lies in mere fantasy.
For example, a breakthrough in better batteries could supplant hydrogen. Better solar cells could replace or win out in this race to the fuel of the future. Those, I see, as the three big competitors: hydrogen, solar cells and then better batteries.
I've always believed that humans are good at heart. But there's always the exception.