You're ignoring improvements in fracking that have only happened in the last 15 years. Certainly fracking itself isn't new at all, the first attempts date back under a century, but the cost has come down. Most fracking was done using vastly more expensive chemical concoctions which were largely unsuccessful in a lot of shale formations—until someone tried with a solution that was mostly water. Not only was it more effective, it was half the price!

Moreover, fracking came in to vogue due to drilling for natural gas, not crude.