Not so sure about the pure oxygen. I've done many beers in the 8.5-12% ABV range and have never used oxygen. I do shake the crap out of them at the lower pitching temps (more O2 can be absorbed at lower temps), and also give my friends a healthy dose of yeast nutrient. But I have yet to have a stuck ferment or one that didn't go as low as I wanted.
All that said, I should try pure oxygen on some batches to see how it might contrast. Never really know until you try it yourself.
You can get away brewing high ABV beers with the shake and pray method, and most times if you pitch enough yeast you will not get a stuck ferment.
My comment was more geared towards increasing the quality of the final product. Pure O2 will provide oxygen levels that shaking or an air pump will never attain...and the impact on the final beer is startling.