Why is adoption of "planning as a service" not more widespread?

Lora Cecere @ AMR Research has a nice post title "Wanted: Experience." Her assertion is that supply chain planning software companies are not taking responsibility for the results achieved. Lack of trained "planning" analysts and lack of demonstrated continued results are couple of symptoms.
She writes:

"Companies still struggle with the concept of planning."
"I do think that software leaders do have a responsibility to train companies to use their software. ... True value in software happens when companies use the software and an ecosystem evolves to drive excellence through usage."

I think one answer is for companies to outsource their planning processes to specialized providers of the service. Here is a (by now 4 year old) case study.
i2 at Panasonic: "i2 set up a competency center in India for working closely with Panasonic and its channel partners for analyzing POS data, promotional activities, and market intelligence reports, which helps to ensure accurate demand forecasts, replenishment plans, and safety stock levels." There are companies that procure services for one time analysis. But there are not many that have adopted "planning as a service." Why is that? Your theories / thoughts?
Karthik