The concept of Peak Production in the game causes the resource extraction to fizzle out before it can extract all the recoverable resources. It does this by reducing the production capabilities as soon as half of the resources have been extracted. (The half-way point is marked by the blue line) This results in an S-shape. You can try to push the fizzle out point (where the production flatlines) with "Expand [resource]" cards. But you can not fight it. Sooner or later your production will be reduced to or around 0. "Expand [resource]" cards become increasingly pointless and do nothing towards the end.