Sorry,
Loose rivets, you'll have to explain
why "it simply will not work". The carbon-based energy supplies exploited to date have been the 'easy' ones. This makes perfect sense - if oil from field A costs $10 a barrel and from field B it's $20, then field A gets exploited first. While oil remains at $15 a barrel, field B will never get exploited. For similar reasons, many fields have more oil left behind than has been extracted - it simply hasn't been economic to get it out of the ground.
Then there's oil shale - more potential energy than in all the oil discovered up to now (3 billion tons in Germany, alone) - see
World Energy Council. We'll need new technologies to turn this into a usable product, at present it takes more energy to extract it than you get when you burn it, but I'm an optimist
.
NB I'm no energy expert (maybe Loose Rivets, based in Texas, is), and I know there are several PPRuNers who are, so I now sit to be corrected!