Avatar 2: The Sequel

I never understood why fossile fuel is still so widely used. From a chemist's point of view oil is such a versatile ressource. For me burning fossile fuel is simply like heating a house by burning lego bricks. (Which is possible, as ABS-plastic the lego bricks ar made from is not self-extinguishing.) It is common knowledge that fossile fuel is limited an one day we will have to develop methods to replace it by renewable ressources. Why not starting now to massively develop alternative and renewable energy sources, as we will have to do it anyway in near future?