What will people do when oil becomes too scarce (and thus expensive) to waste moving personal metal boxes around on the road? I.e. what are the alternatives to the use of fossil fuels for personal transport?
At some point, that question will have to be answered. Maybe that might for the next generation but I'm guessing it'll need to be answered sooner than that. Why? Because there are 7+ billion humans on this rock and they mostly aspire to the profligate lifestyle of the west (as typified by the lifestyles enjoyed by the US, beamed in to their homes by the TV). Can 7+ billion people (it'll be 10 billion within perhaps 30 years (i.e. one generation)) all have cars that run on fossil fuel? Got to say the answer is "no". So what are we going to do?
Maybe, the answer is "we'll scrap personal transport" or "we'll do what we evolved to do: walk" or "we'll fight increasingly nasty wars" or "we'll come up with a clever way of motivating personal transport that doesn't require the burning of fossil fuels in the device itself".
If the last answer is the one we go for, why not try to develop it now? Why not try things now?
Or do we just shrug our shoulders and say "I don't care, I want my gas guzzler today and I don't care about tomorrow".