"once you'd gotten used to creating your presentations in PowerPoint, you wouldn't want to go back to not using it."
I know plenty of people who, even after learning how to use a better tool go back to the first one because it;s how they think. For example, someone in my home still uses a computer like it were running DOS. That is, I want ot open a word document, I first open Word. Same for Excel, open the app first as opposed to using the file system where you go to file you want and let the app open.
As for me, I still do most of my graphics with Windows Paint. When I need better drawing, I use the draw program that comes with OpenOffice.