In fact, the WEC report, Energy for Tomorrow's World, makes it clear we cannot foretell the future and has three cases to illustrate alternatives which are all realistic -- though with varying degrees of challenge. One of these cases indicates that by the year 2100 fossil fuels could account for only 15% of global primary energy supply. In the highest fossil fuel case the proportion is halved from current levels.
Even assuming the many uncertainties surrounding the climate change issue were to be resolved in favour of the general circulation models currently attracting widespread interest, global mean temperature rise would be barely over 1¡ C in the low case, and global annual CO2 emissions from fossil fuel combustion would be more than 50% below 1990 levels. In the low energy and fossil fuel demand case, new renewable forms of energy (excluding large hydro) could account for 50% of global primary energy supply, and wind energy for up to 1.8 Gtoe (gigatonnes oil equivalent), or 9%. Further details are available in the WEC's New Renewable Energy Resources: a Guide to the Future.
This is not the picture you portray. You have taken the interpretation of our work by Chris Flavin and Nicholas Lenssen at face value. It is, as usual, better to go back to the original if one wants an accurate portrayal. If we are proceeding more slowly along a low energy demand/fossil fuel use/energy efficiency trajectory than many would like, this is a reflection of general attitudes and behaviour among energy consumers and policy-makers. The WEC has made the options clear enough.