gh patriot -
The short answer is "no," you don't need to do a lot of pp to produce great photos. Look at the pic by genielamb in this
link as an example.
When starting, lots of people tend to foucus most on getting better straight out of the camera shots. With better SOOC shots developed through experience and practice, you'll start to see if you want, need, or would like to improve any part of your photos with pp.
And remember that all this is subjective. If you find that you like your shots with no pp, with just subtle pp, or with a lot of pp that makes the photo resemble a painting, then that's what's right for you.
So, don't worry about pp. You'll do fine with or without it, and your experience and tastes will show you the way.
Good luck and have fun.