My stretch marks are severe (I don't have very elasticky skin *does that make sense LOL*), I have bad marks on my belly from my pregnancies on top of being obese. The Marks range from 1 cm to 1.5 inches thick and go from my pubic bone all the way up to my ribs... and from one side all the way to the other.
I never figured they'd go away. But even after losing 30 lbs, they're fading. They're now blending in with the rest of my skin tone. I don't think you can ever completely get rid of them *unless you decide to do a tummy tuck later on*, but for me, they're not nearly as noticeable... and after I lose more weight I'm sure they'll fade even more.
Cocoa butter is always good to help keep it moist though