"Going To Market(place): The Future of Procurement"

I've just listen to the excellent webinar called "Going To Market(place): The Future of Procurement" and was wondering about the impact on the supplier base. Mary Hetherington, Director of UK Group Procurement, AXA, is currently piloting Amazon Marketplace, the e-commerce platform owned and operated by Amazon, with IT peripherals and facility management products. If the pilot is successful and AXA is a typical customer, what proportion of the supplier base is likely to be removed and replaced with Amazon Marketplace?