As I said it the post, though not as clearly and eloquently as you, SaaS vendors are relying too much on the medium of distribution rather than the added value service the medium provides.

The challenge vendors face is trying to differentiate their offering so that higher margin clients (large enterprises) get better value than their current, low-margin clients (SMBs). The core concept of cloud computing essentially makes the offering the same for all users.

More here – http://diversity.net.nz/lets-discuss-saas-some-more/2007/07/08/

The SaaS model provides so much economic benefit, but currently since its only being widely adopted by small and medium companies, those cost savings are being passed onto the users.

As I said in the article, SaaS vendors should be able to grab a much bigger piece of the cost savings pie when providing for large companies.

One major problem I see to adoption is that the IT departments in large companies will be very resistant to changing the model that keeps them employed. Anyone with the authority to make the decision (non IT upper management)to go with a SaaS vendor probably doesn’t know all of its potential benefits.