How would they do that? Power plants and generators need a load, cars and other transport needs somewhere to go and something to carry, and other infrastructure to burn fuel at any sort of scale just doesn't really exist except at the wells themselves. Flaring infrastructure was designed to burn large amounts of unprofitable gasses coming up with the oil and to prevent dangerous pressure build up, not waste tons of unrefined petroleum. Beyond the added pollution it's a huge safety risk that could destroy a bunch of wells.