Then why is it that PP isn't NEARLY as easy to use or admin as some of the free scripts, and doesn't even have several important features that others have?
I think that's an oversimplification. There may be certain aspects that are easier in other products, but overall, PhotoPost is a much more powerful application and offers much more customizability and functionality than anything else out there. It's also extremely fast and stable, and supported by paid developers -- these things are important to most site owners.
If you can list specific "important features" that you think PhotoPost doesn't have, and other products have, please do. It may be that you're unaware of PhotoPost's latest capabilities.