Notice the pixelization of the JPEG images and the loss of detail in the grass. Clearly, you will better recover from your mistakes if you shoot RAW.
Now you say that you always strive to get it right in camera. That is a worthy goal and one we should all strive for, but the fact is, you CAN'T always get it right in camera. The camera does not have the dynamic range of the human eye. It is often impossible to get an image that accurately reflects what you see without some post processing.
Look at the following image and think about how you would get it right in camera: