It seems I have offended you by providing a subjective opinion as to why your dream, and mine, are on distinctly shaky ground.
I'm not offended at all, I just think your reasoning is flawed and ignores history.
And any form of transportation that can be readily converted to other energy sources will boom. This would include hybrid/LPG vehicles, as you have mentioned.
My point exactly......why is it that you believe that the engineers at GE, Williams, Rolls Royce etc will sit on their hands and watch the rest of the technological world pass them by? In fact future reality may prove to be completely the opposite of what you assert. No other industry in the world has such an overbearing commercial imperative to reduce their fuel costs as much as aviation. Added to this is the fact that the hopelessly small margins in aviation drive airlines to buy the most fuel efficient aircraft available forcing constant improvement from the big two manufacturers lest they miss out on that next big order. As you have already stated economics is the driving force behind such change so why will aviation stand still while every other industry adapts?
The Comet.