You are missing the point. The idea is that, as Facebook's and Google's way of managing their large networks become more popular (due to it being more efficient and less expensive), eventually all companies will move towards it. This will negate the need for the expensive Juniper and Cisco switching/router gears which the companies relies on for their revenues.
A sales team is only as good as the product they sell. They can continue to sell a product which is not competitive but only for a while before the market catches up and pushes them down. The effect will not be short term but could be long term (assuming that what article is saying is true).
Cisco's future maybe bleak but not because we'll all move to Facebook's and Google's model. The systems they build are at massive scale, and heavily optimized to their workflow. Cisco equipment is in general designed to handle a heterogeneous workload, in a variety of deployment scenarios.
A sales team is only as good as the product they sell. They can continue to sell a product which is not competitive but only for a while before the market catches up and pushes them down. The effect will not be short term but could be long term (assuming that what article is saying is true).