Look up oil and gas decline curves and you'll see that a faster declining oil production means you'll get a lot less oil out of the ground over the next 10 and

Look up oil and gas decline curves and you'll see that a faster declining oil production means you'll get a lot less oil out of the ground over the next 10 and 20 years. And given a reasonable discount rate of 6% mean oil in 10 years is worth half of oil today and oil in 20 years is worth a quarter. You also run into efficiency issues. Running a high volume rig much more expensive than running a low volume rig.