I only boil my extract batches for 30 minutes and if I steep they get 45. I rely on a quick chill, plenty of healthy yeast and a consistent cool ferment. My goal isn't head retention, but it is a nice side effect. Extract almost always gives me good results.
There are many more variables to head-retention than just the wort itself.
First place to look is the glassware. Then carbonation levels and how the pour or dispensing is handled. After this look towards the brew itself and how it was made.