How is SaaS different?

I can't explain better than this image, from an article at Sun site...

The title explains all about the rate of innovation & change requirements directly from users to product development team. NOTE: SaaS is selling directly to users instead of buyers.

Then look at the simplicity of the SaaS model! Doesn't simple things scale better also? What about the new feature requests & bug fixes? It used to be months & years...Now it's about days,weeks & even hrs to get things done.